The terminal characteristics of GaN based HEMTs in RF operations at high operational biases differ from those obtained in DC operations. This phenomenon is generally referred to as a knee walkout. In this work, we construct a physical transport model for a 1um gate GaN HEMT by calibrating its I-V characteristics and then perform TCAD level simulations of a class A amplifier in a mixed circuit. Our results show that the knee walkout is linked to charge trapping in the buffer of the device and depends on the DC operational bias as well as the maximum drain voltage. The developed TCAD simulation methodology is essential to assist in reducing the negative impact of traps in heterostructure by design alternations aimed for particular RF applications.

Dimensions Optimization of LDMOS (Laterally Diffused Metal Oxide Semiconductor) Field Effect Transistors, utilizing SOX (Step Oxide) for drift region structuring, is studied. Using TCAD modeling and subsequent layout and process variations, based on TowerJazz's 0.18µm BCD (Bipolar-CMOS-DMOS) process, state-of-the-art BV (Breakdown Voltage) and Rdson (On-resistance) are achieved. The figures of merit for voltage rated applications up to 50V are similar or better compared to more complex approaches. Drift length, ratio of field-plate-length over SOX, as well as SOX thickness variations, enable very competitive BV / Rdson rates of > 55V / 30mΩ•mm2. Fabricated devices demonstrated similar figure of merit and a BV range up to 70V.

All high frequency radio and radar applications require electronically controlled functional operation in the form of high performance switches. This control functionality often must satisfy a number of requirements, such as, linearity, high isolation, low distortion, minimal signal loss, high third order intercept, switching speed, and power handling; in addition to simply being able to switch RF signals from one electrical path to another. This paper compares the performance of recent advances in AlGaAs/GaAs PIN diode integrated switches to the capabilities of more traditional silicon and HMIC PIN diode, GaAs pHEMT, and SOI CMOS switch configurations This comparison is also extended to include two new alternate GaN HEMT technologies

High-power millimeter-wave amplifiers are required for various new and emerging applications, such as point-to-multi-point wireless high-data-rate communications over multi-km ranges for residences and businesses. Driven largely by these requirements, both civilian and defense-related, researchers over the last decade have dramatically increased the power and bandwidth of a variety of vacuum electronic amplifiers in the millimeter-wave regime. The Naval Research Laboratory (NRL) has played a key role in the development of the science and technology that has made possible this increased performance. One attractive class of devices to arise from these efforts is the power booster, a relatively low-gain but very high-power amplifier that can produce significantly higher power than state-of-the-art amplifiers driven by comparable electron beams. At Ka band, NRL power boosters have produced from 1.5 to 4 kW of peak power from electron beams of ~20 kV and up to 600 mA. The 3-5 dB gain of these amplifiers allows compact designs and high interaction efficiency. For example, with a multistage depressed collector the 4 kW output power device can achieve a power added efficiency of >40%.

Passive microwave imaging system must have various special calibration at the used temperatures. There described in technical details principal and responsible simple area matched loading for the calibration matrix radiometric 8 mm receiving array which has VSWR not pure than 1,10.

Determination of antenna radiation pattern is an essential step for any communication systems. Although, there are several techniques available some of them are expensive, unreliable or complex. In this paper, a new measurement method of antenna radiation patterns that overcomes some of these issues is presented and implemented. The method is based on acquiring the radiation intensity in different angular positions, based on fixed-line-of-sight setting, far-field measurement techniques and probabilistic analysis. The method provides a fast and simple mechanism for verifying antenna radiation patterns. The current method is used to determine the radiation pattern of a Yagi-Uda antenna with six parasitic elements of variable length and is compared with well-known theoretical models, showing good results.

There are several approaches of verifying and improving the antenna measurement accuracy in near- and far-field ranges. Additional measurements and a proper post processing of the measured data can be used for improving the measurement accuracy. A few of the methods have been elaborated in that concern: a) De-convolution, b) Time-domain gating, c) Reflection suppression (pattern oversampling), d) Pattern comparison, in which a few measured patterns are then superimposed and averaged, etc. An advantage of the proposed method is that unlike the "traditional" pattern comparison method, in which for stray signal depression at far-field angles the exact locations of the antenna are required, here only 3 equidistant locations are sufficient for suppression of any stray signal incident from arbitrary directions

Using Drones or UAV for different applications is the future, currently there are almost 70 companies that design and manufacture Drones or UAV, that only include commercial usage. There are 3rd party companies that focus on military use of Drones and UAV. The number of companies increased from 6 in 2015 to 70 in 2016, and the number is still growing. One major application is emergency response drone for civilian applications. There is no standard platform of Drone and rules & regulations are not well planed yet, so simulation and testing is strongly recommended. Currently, most drones do not fly in bad weather because they are not designed to do so. In this paper, we will show the problems a drone can have in bad weather, like lightning strike and rain. Using simulations, we can show the lighting strike effects and how to solve the lighting strike problems.

Some advanced building principles for circuitry optimization of a base station for emerging fiber-wireless networks were proposed and discussed. They include the simultaneous application of low cost and power-efficient LW-VCSEL in downlink and uplink channels, direct modulation of LW-VCSEL in period doubling state using its intrinsic modulating feature, and direct modulation of optically injected LW-VCSEL in period doubling state using the effect of enlarging its modulating characteristic under impact of strong optical signal of comparable frequency. Following them, we proposed two simple, power- and cost-efficient versions of base station layouts that may find a promising application in the future 5G networks.

Large array sizes needed to deliver the necessary link budget in cm and mm wave bands require channel estimation of multiple beams. Impact of channel estimation overhead on achievable rate in fluctuating 28 GHz channels is examined. It is found that finite coherence time and bandwidth limit useful number of joint Tx-Rx elements. For slow pedestrian channels 6,000 Tx-Rx elements reaches rate saturation, while vehicular speed channel (30 m/s) reaches its limits at about 400 joint elements. For an obstructed LOS channel (25 dB excess loss) reaching 10x the rate of a reference cellular channel requires 28 dBi joint Tx-Rx antenna gains.

The future development of on- and inter-body sensors is going to make these devices more common in people's everyday life. Eventually, these Body Area Networks (BANs) will appear in more and more areas of human life and will grow in numbers. Increase of the density of BAN networks will raise problems of coexistence between them, which is, in some ways, similar to the way people themselves experience problems with the growth of population. Various approaches for the coexistence ability of BANs were developed. In the present paper, we will examine a number of such approaches, which are based on each BAN's ability to achieve knowledge according to transmissions scheduling of interfering BANs and using this knowledge for collision avoidance. Such ability can be achieved by using an algorithm for detection of interfering BANs transmission parameters, which was published in our previous publication. Here we examine the actual usage of this algorithm for inter-BAN collision avoidance.

The University of Oklahoma's Advanced Radar Research Center has been developing several weather radar systems that leverage modern phased array technologies to provide advanced functionality as well as multi-function capability. This paper details the latest achievements during the development of these systems, as well as some notional plans for future research opportunities that these systems will enable.

The hyperglycemic state caused by diabetes mellitus has a strong impact on the physiological functionality of the organism. In modern medical research diabetes mellitus is one of the most researched diseases because of its wide spreading in society. One important case is the formation of advanced glycation end-products (AGEs), where plasma proteins like albumin and hemoglobin form covalent adducts with glucose. Also extracellular matrix proteins like collagen and fibronectin form these adducts, which can lead to structural and functional changes in the concerned tissue. An early detection of diabetes assures an early intervention to regulate the carbohydrate metabolism and would lead to an important impact on the health care system. In this publication a non-invasive detection principle based on the measurement of complex scattering parameters in the millimeter-wave frequency range is presented. We demonstrate that with a simple calibration procedure one can use transmission and reflection signals to identify the hypergycemic state of animals. We also will show that using only reflection measurements and signal postprocessing, we can identify the hypergycemic state also without any calibration procedures. The method proposed here can be used to predict diabetes status in animal models and is interesting for application on humans in view of safeness of millimeter-wave radiation. Furthermore the complex scattering parameters give important information about the anatomic varieties between the analyzed skin samples of the different mice strains. In contrast to other methods, our approach is less sensitive to skin variations between animals. In contrast to other techniques, we propose here that it is possible to use the approach without prior knowledge on the physiological and dermatological parameters of the animal (or human) under consideration. In a previous publication [1] we have demonstrated that an in-vivo non-invasive measurement principle based on mm-wave spectroscopy through a skin fold of mice can distinguish between mice stems of different hyperglycemic states. We showed that a PCA algorithm can identify mice stems with different hyperglycemic states using the amplitude of transmission measurement through the skin, but we could equally used reflection measurements. However, these are more noisy when no calibration is applied. In the present publication we want to demonstrate that a combination of the amplitude and phase information for the two measurement channels can be used to identify the different metabolic animal stems, without the need to resort to PCA or PLS analysis, which uses only the amplitude information. We demonstrate that using amplitude and phase information of the reflected and transmitted signals, respectively, provides sufficient information for the early detection of diabetes mellitus. The complex scattering parameters, which are used in the present publication have a clear advantage to the previous approach in terms of online monitoring and ease of data processing. The complex scattering parameters do not only provide the opportunity to identify the different glycemic states but are also calibrated to standard measurements. The calibrated data give more information about the thickness and the tissue properties of the measured skin samples and can be used to evaluate the skin structures responsible for the different responses for several metabolic strains. This is achieved at the expense of necessity of a calibration procedure, which however is a standard task in all measurements employing millimeter-wave equipment. We are currently working towards the possibility to employ only reflection measurements, which would enable very easy measurements on humans. [1] Martin-Mateos, P. et al. In-vivo, non-invasive detection of hyperglycemic states in animal models using mm-wave spectroscopy. Sci. Rep. 6, 34035 (2016).

This work presents the results of studies carried out to confirm the possibility of using bioradar for the fall detection. We used different types of discriminant analysis to classify movement patterns detected by the bioradar into 'fall' and 'not fall' events. Classifiers were tested on the experimental dataset recorded by continuous wave radar: BioRASCAN-4. It contains 338 records of various basic movements (including 51 fall records). For classification features of bioradar signals in time domain were used. The performance of the classifiers was evaluated calculating classification accuracy and Cohen's kappa coefficient

We developed the Eyelid Motion Monitor (EMM), a real-time prototype system for monitoring eyelid motion. The main components of the system are a tiny magnet located on the upper eyelid, a specially designed hardware system for real-time signal acquisition and dedicated computer software for analyzing real-time and off-line modes. The EMM allows to assess ocular and systemic diseases by analyzing upper eyelid movements. We characterize and analyze blinking parameters based on clinical data collected from healthy patients.

The development and improvement of imaging modalities for the early detection of breast cancer remains an active area of research. Microwave imaging has attracted significant research interest as a novel modality for breast cancer detection that presents important advantages over other techniques currently applied in clinical practice. It is known that the dielectric properties of normal and malignant breast tissues differ even at the earliest stage of tumor genesis. Thus, microwave imaging, which detects dielectric in the medium, could be used for early stage breast tumor detection. This paper presents the study results of the Self-complementary Bow-tie Antenna (SCBT- antenna) for microwave imaging. The most important milestones are to select the optimal antenna characteristics for MWI and to model and simulate the array element using specialized software packages.

Electronic steerable active antennas based on all-silicon solutions are rapidly being deployed in a wide range of applications including 5G communications infrastructure, satellite communications terminals, and radar systems. For over 50 years advancements in Si devices have followed Moore's Law allowing today's Silicon to revolutionize applications where previously only III-V materials were used. Silicon is now fully capable of providing high performance devices that work at mmwave frequencies. This enables low cost planar phased arrays to be deployed for volume commercial applications across many applications. This paper focuses on some of those applications, shows that the architectures being deployed across multiple markets are similar in nature, and provides examples of industry leading Si solutions that enable these active antennas.

We consider the physical model of synthesis of Bloch and Rabi-oscillations. Consequently, the new effect of combined Rabi-Bloch oscillations (RBO) is created. The tunneling current in the lattice of two-level fermionic systems, driven by dc-ac electric field, have been calculated. RBO manifests itself in the superposition motion of intra-band and inter-band transitions. In spite of this components belong to the different frequency ranges, the total motion does not add up to their simple linear superposition. It is characterized by their strong mutual influence, which produces non-trivial dynamics and qualitative features of spectrums. An experimental implementation and potential applications of RBO in nano-antennas of terahertz and optical frequency ranges have been discussed.

Nowadays, modern communication systems like mobile phones use antennas that are compact, multi-band, located inside the mobile phone and regularly covered by hand or head. In the meanwhile, the space allocated to them tends to decrease due to the needs of other components and the struggle for reduced overall device size. Furthermore, mobile antennas are very difficult to be fully matched. Up to 80% of energy delivered to antenna returns back and disappears as heating, resulting, amongst others, in call drops, mobile phone heating and higher battery consumption. As a result, the traditional radiating performance goals of antennas are becoming increasingly challenging. In this paper a novel implementation of an antenna tuning closed loop model is presented using Scattering Matrix (S- matrix) approach. This approach uses an antenna tuner as a centric tuning element, it is based on the S-matrix that is a universal metric and achieves a significant improvement in impedance matching and return loss.

We consider a novel concept of a miniature vacuum electronic device (VED), targeting coherent electromagnetic wave generation in the THz range, but not limited to the latter. While in a traditional VED a preformed mono-energetic electron beam is interacting with a slow-wave structure or a resonant cavity, the hybrid cavity under consideration allows for interaction of electron bunches accelerating or oscillating in a Penning trap-like static field configuration integrated with a resonant cavity, formed partially by the trap's electrodes and partially by a dielectric Bragg structure. As a first step, we analyze the energy exchange spectrum between the oscillating bunches and the cavity eigenmodes. While the dielectric breakdown limits the maximal frequency of bunches' oscillations to an order of 0.1 THz, a significant high-harmonic interaction with cavity modes above the fundamental is possible for a large, comparable with the cavity dimensions, oscillating dipole. Proper design of the cavity may allow for interaction of a selected high harmonic of bunch oscillations with a single mode of the cavity, providing conditions for an energy-efficient generation of a virtually monochromatic THz wave.

Cellular structure designs have been proposed as media with negative indices of refraction. Verification of such designs has been accomplished (a) experimentally by observing the direction of a refracted wave after passing through the cellular structure cut in the shape of a prism, and (b) numerically by computing the phase velocity of the wave within the structure. In both cases, the wave behavior was found to be consistent with negative index material. Since the prism shape for the measurements is formed by cutting the structure along the cell walls, the hypotenuse of the prism is periodic. In this paper we show that the observed negative refraction direction could be obtained if the prism material had a positive refraction index np that depends on the negative index nc. In addition, it is shown that within this same material with positive refraction index np, the phase velocity sampled along the walls of the cellular structure will appear to be consistent with the target negative index nc. Our investigation therefore indicates that to unambiguously demonstrate material negativity additional empirical evidence is required.

This paper surveys recent developments in the field of non-reciprocal metasurfaces. We consider in some detail two examples. First, of a magnetic bias based non-reciprocity that is implemented in an ultrathin graphene layer, and second, of thin space-time modulated metasurface that acts as a one-way mirror without magnetic biasing. A comparison between the approaches is briefly discussed. Extension of the concepts for non-reciprocal radiation is also discussed.

An implementation of a flat array antenna with a synthesized shaped beam in the elevation plane and a digital beam forming (DBF) capability in the azimuth plane is presented. Theory used for the beam shaping is based on the Fourier transform method. The beamshaping widens and changes roll-off slope steepness of the array main beam in elevation plane as well as suppresses the sidelobes. The necessary magnitude and phase distribution for the shaped beam is integrated within the corporate feed network of the array, which is printed on a low loss substrate. The DBF capability of the array in the azimuth plane secures a field-of-view of 90 deg at a grating lobe level below -50 dB. The array makes use of an innovative, open-ended waveguide-like, broadband radiating element, electromagnetically coupled to the array feeding network. Thanks to the corporate feed and to the features of the radiating element, the array exhibits a wide instantaneous bandwidth of 28% at VSWR 2:1. A good compliance between simulated and measured performances of the array is presented and discussed.

This paper discusses a quarter-wavelength spaced infinite linear antenna array consisting of identical two-element cells. Elements inside each cell are not necessarily the same. Minimal physical value of inter-element coupling is derived from per-cell power balance considerations for generic elements radiation patterns. It is shown that a lower limit on a coupling between the elements exists as a function of their respective radiation properties, reaching -6dB for an important special case of identical well-matched antennas. Conclusions regarding performance limitations of large interleaved TX/RX arrays are derived from this result.

This paper describes the first series of measurements to characterize and map spatial spectral reuse and total system throughput as a function of the location of multiple users within the coverage area of the "OneCell" virtualized Cloud-RAN smallcell deployment. The measurements demonstrate that the adaptive frequency reuse algorithm which creates virtual cells from the set of active users each 1 millisecond TTI provides multiple units of reuse within the single borderless cell. The transition from one unit of reuse to two full units of reuse was observed. Total system throughput approaching 240 MBPS in a 20 MHz allocation was attained with two UE's.

This work considers routing in random wideband wireless-adhoc-networks (WANETs), where each node is equipped with a single antenna. The analysis uses a detailed model of the physical layer together with an abstraction of higher communication layers. We assume that the nodes are distributed according to a Poisson-Point-Process and consider routing schemes that select the next relay based on the geographical locations, the channel gains of its neighbor nodes and the statistical characterization of all other nodes. This paper proposes a novel routing approach that uses multiuser subcarrier allocation in which a transmitter can exploit the instantaneous channel gain at each gain, and to allocate the bins to multiple next-hops; I.e., each transmitter can have multiple next-hops, simultaneously. In this work, we present the exact optimal solution for the analyzed scenario. The optimal routing is given as a maximization of a routing metric which depends solely on the known partial channel state information (CSI) and includes an expectation with respect to the interference statistics. The optimal routing scheme is important because it gives an upper bound on the performance of any other routing scheme. We also present sub-optimal routing schemes that only use part of the available knowledge and require much lower computational complexity. Numerical results demonstrate that the performance of the low complexity schemes is close to optimal and outperforms previously published routing schemes.

We present TeamBoost, a collaborative solution enabling a client device to leverage the cellular links of its nearby devices to enhance its overall connectivity to the cloud. Team- Boost architecture can serve for numerous IoT applications, yet in this work it is proposed as an alternative to conventional and costly H/W upgrades aiming to maintain up-to-date vehicle connectivity experience throughout the vehicles extended lifetime. TeamBoost's approach is to build upon a relatively new and yet well established Multi-Path TCP (MPTCP) protocol, exploiting the natural way that MPTCP splits an end-to-end single TCP stream into multiple MPTCP sub-streams that traverse different communication links. TeamBoosts novel implementation provides a non-trivial extension of MPTCP to TeamBoosts collaborative setting, where sub-streams are relayed through multiple independent devices. To support scalability of the system, the implementation of TeamBoost on the devices is restricted to the user-space, allowing it to be installed as any other application supported by its operating system. Experimental results show the benefits of TeamBoost, in terms of both connectivity performance and robustness.

Oblivious relay serves users without a need to know the users error correcting codes. We extend the oblivious relay concept to channels with interference which is known to the transmitter but not to the receiver. We show that when the interference is known non-casually, it's influence can be overcome wholly and that in simpler casual schemes the performance is usually within the shaping loss of 0.254 bits/channel use from the optimal performance attainable with large lattices. Our system uses structured modulation and coding.

Cross-eye (CE) jamming is a technique of electronic attack that can provide self-protection of aircraft against guided missiles using monopulse type radar. Implementation of a CE jammer using a retrodirective channel in a non-reciprocal electronic warfare system requires an appropriate system design and a correction process to achieve reciprocity. This paper defines a model of a CE jammer that uses digital radio-frequency memories, Active Electronically Scanned Arrays (AESA), and a system correction process. Further, the paper defines a simulation procedure for jammer performance estimation and system evaluation. The procedure is demonstrated by performing a parameter sensitivity study where the effects of dynamic variations in AESA model parameters on CE performance are determined.

The features of the IEEE 802.22 standard are analyzed to solve the problem of building a broadband communication channel for a remote control system for unmanned vessel. Comparative modeling of the coverage areas of the communication systems with IEEE 802.22 and IEEE 802.11 for concrete region is performed. The advantages of systems realized with IEEE 802.22 standard are shown.

The paper presents the generalized approach to the modeling of Doppler-polarimetric radar signal spectra for the rain and snow conditions. This model is enhancement of existent rain model to the cases of dry and wet snowflakes. The dryness parameter is proposed to select the hydrometeor type. Its value is varying from the zero to unit, where the zero value means the rain, the unit value means the dry snow, and the value in between correspond to the wet snow. The proposed model can be used to analyze the meteorological characteristics and parameters, such as reflectivity, differential reflectivity, Doppler polarimetric spectra, spectral differential reflectivity and others including the turbulence influence.

This work presents the design recipe, fabrication process and characterization of tissue-simulating materials, configured as a physical model to mimic the electrical and some physical properties of an abdominal cavity. The complete three-layer design is called the human core model (HCM) see Fig. 1. To our knowledge, presented is the first hybrid skin-muscle phantom developed to mimic the electrical properties of the intervening tissue layers of an abdominal cavity within the frequency band of 1 GHz - 2 GHz, a band of interest for human body sensing due to its deep detection depth.

Microwave ablation is a promising technique for the treatment of cancer in various body organs such as liver, kidneys, lungs, and bones. This is especially suitable in cases of patients that are not viable candidates for surgical resection. During the treatment, an ablation antenna is inserted into the tumor, and microwave power is applied for a number of minutes in order to burn the cancerous cells. Microwave ablation antennas should have small diameter to reduce the invasiveness of the treatment. In this paper, we propose a new method to reduce the microwave ablation antenna diameter. We propose not to stick to a conventional 50 Ω coaxial cable, but instead make the antenna as thin as enabled by common manufacturing technology, and match its lower than 50 Ω impedance to the 50 Ω feed line outside of the patient body. In this work we present a balun-less, extremely thin, antenna designed for liver tumor treatment at 10 GHz. CST Multiphysics simulations demonstrate reasonably spherical ablation zone around the antenna tip.

A resonant cavity-based analytical model is adopted in this work to predict the resonance frequency behavior of a microwave biosensor, radiating into a dispersive medium. A specific application in the framework of non-invasive sensor for the monitoring of glucose level is considered, by providing both numerical as well as experimental results.

Chirality discrimination is of a fundamental interest in chemistry and biology. In optics, near-field plasmon-resonance spectroscopy with twisted-photon probing fields is effectively applicable for analyses of large biomolecules with chiral properties. The measured forms of chiroptical intensity are inversely proportional to the wavelength of the probing radiation. That is why use of microwave radiation to detect chirality is usually considered as a non-solvable problem. However, direct detection of biological structures in microwave frequencies is considered is a problem of a great importance. In particular, it concerns direct detection of biological structures and understanding of the molecular mechanisms of nonthermal microwave effects. In this paper, we show possibility for microwave near-field chirality discrimination analysis based on magnon-resonance spectroscopy. The near fields originated from a small ferrite-disk resonator with magnetostatic-magnon oscillations have intrinsic chiral topology. The proposed sensing is addressed to microwave biomedical diagnostics and pathogen detection and to deepening our understanding of microwave-biosystem interactions.

A novel high factor multiplication circuit is introduced in this paper, generating F-band frequency signal out of X-band input. The 9th harmonic of the input is generated by a single differential CS stage, subsequently amplified by a transformer-coupled CS F-band PA. The circuit, implemented in 65-nm CMOS consumes only 160mW of DC power and a small area of 0.4 mm2 including pads, achieving up to +9dBm output power at 110.25GHz, and 16.1% 3-dB bandwidth in the range of 97-114 GHz and harmonic suppression better than 25 dBc.

This paper presents a dual-modulus flip-flop-based frequency divider with programmable division ratios by 4/5 designed in a 0.13 um CMOS technology. The divider is based on a modified CML D-latch topology, for high speed operation and a low power consumption. The AND gates used for realization of dual-modulus operation are integrated directly into the D-latches to achieve low power consumption and minimum gate delay. This modified circuit topology is verified in measurement, exhibiting operation up to 13 GHz. A broadband output buffer is included to drive a 50 Ohm measurement equipment. The divider by 4/5 including a 50 Ohm buffer draws 21 mA from a single 1.5 V supply. The active circuit including buffer consumes a chip area of only 130 um x 72 um.

We introduce a linearization technique for dual-band transmitter, consisting of two power amplifiers (PA) combined in parallel to a single antenna for 802.11ac very high throughput (VHT) intra-band non-contiguous carrier aggregation signals. The proposed technique is based on low power and narrow-band signal injection to compensate for out-band third-order intermodulation distortions (IMD3). Efficiency degradation due to mutual loading is addressed by designing the PAs to introduce high output impedance. We achieve a spur level of 65dBc and 0.5dB power loss due to PA loading. The high output impedance characteristic, together with IMD3 compensation, enable diplexer-free transmission of two carriers along the aggregated transmission band.

This paper presents an experimental study on modulated sidebands in the output spectrum of a millimeter-wave (mm-wave) CMOS voltage controlled oscillator (VCO). The results are used to calculate the injected current into the resonant tank in dependency on its locking range. The measured and simulated parameters match well to the analytical formulas from literature. These parameters are a measure of the oscillator's sensitivity regarding injected periodic interferences. The resulting effects can cause injection locking or injection pulling to a signal in the periphery which degrades the oscillator's output spectrum significantly. This is a design challenge when the oscillator implemented in highly integrated systems, as e.g. in system-on-chip solutions.

In this paper, a double ridged horn antenna with a unique ridge shape, such that the sidelobes in E-plane and H-plane are reduced, is presented A VSWR of 1.8:1 for 2.7 - 3.5 GHz was achieved. The measured results were in very good agreement with the simulation results.

The potentialities of non-diffracting Bessel beams in the framework of through-the-wall applications is outlined in the present contribution. To this end, two specific analyses are considered, namely the study of Bessel beam propagation through a stratified dielectric medium, which is assumed to model the 'wall', and the investigation of Bessel beam scattering by a dielectric sphere, intended as sensing target. Even if this preliminary analysis is conducted by assuming an ideal non-diffracting Bessel beam, generated from an infinite (impractical) aperture, future studies will be devoted to the development of analytical models to predict the behaviour of a Bessel beam from a practical, finite dimension aperture.

A Moebius loop magnetic field sensor is a circular loop consisting of two solid-shielded 50 ohms coaxial "arms", which are split at the top to form a very small gap compared to the loop dimensions. The center conductor of each coaxial arm is connected to the shield of the opposite arm. The Moebius loop antenna can be used in very harsh environment conditions that occur during laser-target interaction (EMP and ionizing radiation). The laser and target chamber system is a high power (PW level) and ultrashort (tens of fs) laser beam, which heats the target inside the vacuum chamber (VC). The measurement system chain is constructed from 50 ohms of well-shielded coaxial cables between the Moebius loop antenna, an algebraic differential signal combiner (BALUN), and an oscilloscope protected at input through a high voltage pulse attenuator. Additionally, there are delay parameters in time that characterize the cables' contribution between antenna and BALUN. There is a practical guideline that combines graphical information with analytical work to effectively study the local stability of models involving delay-dependent parameters. The stability of a given steady state is determined by the graphs of some function of delays parameters.

In a previous work we developed a model for radiation losses in two conductors TEM transmission lines in free space. In this work we develop some fundamentals to generalize the above model for two conductors in dielectric insulation transmission lines.

Planar monopole antennas with patch rectangular has been proposed for applications in UWB. New configurations are proposed using a meander technique, with three different designs of meander line antenna (MLA) are investigated, with increases meander lines. The CST Microwave Studio software is used for simulation designed process.The antennas are fabricated on two substrates differents a FR-4 and RT5880 Rogers Substrate printed board using an etching technique. The graphics simulation and measurement results for the return loss are presented.

In this paper, we like to suggest a spectrum efficient WR (windowing and restructuring)-OFDM system for 5G and B5G (beyond 5th generation) mobile system. The figure-of-merit for the 5G and B5G waveform is the spectrum efficiency. Especially, OOB (out-of-band) power spectrum must be reduced to increase the spectrum efficiency. Filtering and windowing method have been used for the OOB power reduction. As filtering method, UFMC and FBMC have been famous as a new waveform for 5G system. Similar to OFDM system, these techniques use multi-carrier, but they have sharper OOB spectrum. Due to the very complicated process and some difficulty to the realization, windowing method has been enlightened. In the windowing method, WOLA-OFDM (weighted overlap and add - orthogonal frequency division multiplexing) system is the most representative windowing method. However, the WOLA-OFDM system has serious problems. Due to the copy and addition processes, time resource will be slightly sacrificed and the other is that the left part of the copied and added parts will invade into the right part of the previous OFDM symbol. This is very serious data damage even before the transmission. In this paper, we like to suggest a spectrum efficient WR-OFDM system that shows competitive OOB spectrum characteristics and is designed by simple some modification of the conventional OFDM system. Basically this is similar to the conventional OFDM system, but windowing process has to be included after the CP (cyclic prefix) addition stage. By adding this windowing process, we can get the desirable OOB (Out-Of-Band) spectrum characteristics that are very important to save the frequency resources and competitively similar shape to the OOB spectra of FBMC and UFMC system. As simulation results, it is confirmed that OOB power spectrum of WR-OFDM is quite comparable with the existing waveforms. Also, different power spectral densities of the proposed WR-OFDM system are shown depending on the different windowing function. Among the several window functions, Kaiser window function is the best and Hamming window is the worst.

With the proliferation of smart phones and tablet computers, the demand on transmission rates of wireless communication systems has grown exponentially. In order to provide high-data-rate access in mobile and outdoor environments, cellular systems have to use more and more spectral resources. Filter Bank Multi-Carrier (FBMC) is considered as a possible candidate for 5G. Filter bank multicarrier offers superior spectral properties compared to Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM). In this paper, we present snapshots of simulation we did, that examines the feasibility of the method over OFDM in terms of BER, Capacity, Interference from adjacent channels and the influence of non-linear amplifiers. The article will also review the following topics: Fading, Propagation of millimeter waves and FBMC- MIMO. At the end we provide a list of references with an in-depth coverage of the application at hand.

The purpose of the paper is to research and modify the existing LTE-A device-to-device (D2D) physical layer design for the application of the high mobility vehicle-to-vehicle (V2V) communication scenario. To achieve the goal, the training sequence assignment of the demodulation reference signal (DMRS) of the D2D specification is modified and the two possible assignments are proposed in this paper. One modification is the time-domain DMRS assignment. It is designed to extend two DMRS symbols to three or four DMRS symbols during one subframe period. Another modification is the frequency-domain DMRS assignment. It is designed to increase the subcarrier spacing 15KHz to 30KHz or 60KHz. In the above modifications, the signal bandwidth is retained to be the same as the D2D specification. Based on the previous design, we have multiple DMRS assignments to provide the low, medium, high density training sequences, which can be useful for the different mobility V2V communication systems. Simulation results confirm that the proposed DMRS assignments with MODEM and CODEC processing can provide better quality and the efficient data rate performances for the different high mobility scenarios.

We introduce a novel technique for improving PA efficiency and coverage of communication links, especially advantageous for the uplink at high frequencies (HF). The technique is based on a superposition of at least two DFT-s-OFDM (a.k.a. SC-FDM) signals, whose modulated symbol sequences and pulse shaping functions are coupled in a specially crafted, predefined manner. The resulting low-PAPR waveforms enable transmission with essentially no output power back-off (OBO), complying with rigid spectral requirements even when using PAs with highly non-linear behavior, expected from 5G cost-effective RF solutions. A relatively simple modification of a plain DFT-s-OFDM transmitter is required to support these waveforms. Their inherent controlled ISI is handled at the receiver via low-complexity BCJR-type demodulation, yet detection losses are small relative to the transmit power gains, thus yielding large net gains in link budget compared to competing transmission schemes.

Golomb-Rice coding is a simple and fast data compression technique. It has been used in many areas such as image compression, video compression, audio compression, wireless sensor networks and others. Since Golomb-Rice coding is a parameterized (k) algorithm, its performance depends on the optimal code parameter k* for the given sequence of samples/integers. In this paper, two simple procedures are proposed to estimate the optimal code parameter k* of Golomb-Rice coding for encoding the given sequence of samples efficiently. It is shown that Golomb-Rice optimum code parameter selected under the first method is always within the upper bound and lower bound calculated from mean value of the source and the additional cost due to suboptimum code parameter under the second method is not more than one bit per sample. However, it minimizes the number of computations required by first method. It is also experimentally observed that the parameter estimated by the first method is same as the actual Golomb-Rice optimum code parameter.

In this paper Continuous Wave Step Frequency (CWSF) is evaluated as possible modulation for radar sensors aimed to detect small quadcopters at short range.

GB-InSARs (Ground-Based Interferometric Synthetic Aperture Radar) have been demonstrated able to detect changes and even the target elevation when they are provided with a mechanical system for rising the radar head. In this paper a novel acquisition mode is proposed that uses a GB-InSAR with a transponder for obtaining the target elevation, without the need to move the radar head.

There is high demand for LIDARS (Light Detection and Ranging) for advanced driver-assistance systems (ADAS), in particular for autonomous cars. The paper presents the challenges associated with the implementation of such LIDARS using cost-effective CMOS technology, assuming long-ranges (>100 meter) with a resolution of 10cm. The benefit of CMOS silicon photomultipliers are discussed. Design considerations of a LIDAR with gated timing measurement and multi-pulse approach in a commercial CMOS fab are analyzed using SNR as figure of merit.

A Focusing Transmitarray is a quasi-periodic planar lens that is able to focus the energy of a feed at a spot in the Near Field of the lens. In this work, this kind of lens has been used for detection under low contrast conditions. The use of this lens allows non-contact measurements, therefore increasing the sensitivity of a detection system. The resolution of the lens has been experimentally studied by measuring the separation between two metal strips (high contrast) and between two plastic strips on a foam layer (low contrast). This measurement set-up has been used to detect small objects on a metal plate. This screen reflects all the incident radiation hiding the presence of any small object. Using a focusing lens and a proper, but simple, calibration it is possible to find the object without any ambiguity.

In this paper, a non-destructive and non-contact measurement system for analysis of glass fiber reinforced plastics (GFRP) is presented. The system is based on a frequency modulated continuous wave (FMCW) radar at W-band (75 GHz to 110 GHz). It is demonstrated, that faults like folds or small objects inside the material can be detected. The measurement principle is similar to ultrasonic measurement systems but without the requirement of any coupling media.

This paper presents parallelization strategies for the implementation of imaging algorithms for synthetic aperture radar (SAR). Great emphasis is placed on time-domain based algorithms, namely the Global Backprojection Algorithm (GBP) and its accelerated version, the Fast Factorized Backprojection Algorithm (FFBP). Multi-core platforms are selected for implementation as some combine good performance results with moderate power consumption. The implemented algorithms support several types of parallelization, as the stages of the algorithms can be handled sequentially or interleaved. For the GBP algorithm three different data distribution schemes are investigated. For the FFBP algorithm a successive stage calculation method is compared with a combined calculation method. The performance is exemplary evaluated on the low cost/energy, yet powerful multi-core platform Odroid-XU4. All parallelization strategies show an almost linear speed-up with the number of used cores. Even though a specific multi-core platform is investigated, the design decisions are applicable for general multi-core architectures.

In this paper, the matrix pencil method (MPM) is modified and applied to the 2D range-velocity (RV) spectrum as a high-resolution technique to separate the overlapping point-targets. In order to restrict the computational effort and maintain the real-time capacity, a signal processing chain based on the MPM is proposed. The input data of signal processing steps is a 2D RV spectrum. The modified MPM (MMPM) is employed only in the cases where the required resolution for target separation cannot be satisfied in the RV spectrum. In addition, MMPM makes it possible to estimate the angles of overlapping targets via monopulse angle estimation approach. The proposed method is evaluated with simulation and real measurement.

A compact inductorless phase detector MMIC of E-band and X-band signals is presented. The phase detector is combined with frequency divider-by-8 and CMOS DC output buffer to provide high detector gain. The phase detector sports the detector gain of 0.2 V/rad with very high sensitivity of -42 dBm at the frequency of 75.2 GHz. The circuit realized in an SiGe BiCMOS 0.13um process draws 75 mA with the supply voltage of 4V and is intended to serve as an element of a millimeter-wave carrier recovery system.

This paper presents design and characterization of a broadband low-noise amplifier (LNA) operating in the frequency range from 30 GHz to 110 GHz realized in a 0.35 µm SiGe:C bipolar technology. The circuit achieves a wide bandwidth by means of a T-type interstage matching network combined with an additional L-type admittance inverter. The LNA achieves a maximum measured gain of 18 dB. The measured noise figure is below 10.5 dB in the frequency range from 50 to 67 GHz. The circuit exhibits an output-referred 1 dB compression point of 0.5 dBm measured at 64 GHz. The LNA consumes 25 mA from a single 1.8 V supply. The active chip area is only 300 µm x 240 µm. The presented circuit is suitable for various ultra-wideband applications, such as e.g. backhaul communication systems, broadband on-chip vector network analyzer or millimeter-wave imaging.

This paper presents the performance degradation analysis of a broadband wireless E-band link due to the impairments present in the up-converting mixer. The link, operating at 71-86 GHz, is comprised of a balanced IQ up-converting and an IQ down-converting mixer. In this work, the transmitter IQ imbalance effects of Lange coupler, Wilkinson power divider/combiner, and mixer port matching to 50 Ohm value on the system performance is studied through simulations and is compared to the measurements. Error vector magnitude (EVM) is used as a figure of merit to evaluate the quality of the received baseband signal. A bottom-to-top simulation approach is utilized in order to link the circuit-level design to the system-level design and to provide a tool for circuit designers for application-oriented circuit optimization. This study includes the theoretical analysis, system-level simulation and the experimental back-to-back measurements.

A model for envelope tracking-power amplifier is described to analyze and optimize the power efficiency, bandwidth and transmission accuracy of wireless transmitters. The model comprises of baseband layer, a circuit layer based on transistor level representation and behavioral models and a measurement layer. An accurate model was developed to determine the power losses in envelope tacking under different modulation schemes. The optimization of the power efficiency of envelope tracking transmission systems was demonstrated for a 10 MHz OFDM signal.

Millimeter-wave (mmW) carrier frequencies offer new opportunities to build new antenna concepts, but these high frequencies make it nearly impossible to build an omnidirectional antenna. Therefore, it is important to model the position, the rotation of the UE and the surface orientation of the connected antennas. The corresponding anisotropy must also be considered in the channel modeling. Especially a three-dimensional (3D) channel model taking dual polarization effects into account is required and shall be illustrated in this communication. Here, Radio Frequency (RF) based pattern simulation is combined with the base band link-level simulator.

In this paper; a network architecture is proposed and propagation distances predicted for Digital Audio Broadcasting (DAB), following Uganda Communications Commission (UCC)'s interest in DAB introduction. Using ITU-R curves, field strength values are obtained and minimum field strength values determined for DAB frequencies in the 3rd and L bands. Distances of adequate reception are then established for 1 kW ERP. Band III yields wider propagation frequency-dependent distances, than L-band, of up to 59.36 or 68.7 km for 150 m transmit-antenna height and 74.26 or 83.63 km for 300 m transmit-antenna height. Band III usage is recommended in an asymmetrical network.

Recently, Unmanned Aerial Vehicles (UAV's) are attracting increasing attention for many applications such as increasing the RF coverage, network connectivity, or responding to emergency situations. In urban environments these platforms can provide many benefits such as decreasing the buildings blockage and reflections from distant objects, improving the link budget and the communication system performance by means of path loss and intersymbol interference. In this paper we analyze the channel narrow and wideband properties of the link between a ground terminal and an UAV for mid elevation angles LOS and NLOS conditions. The presence of the multipath phenomenon in urban environments due to reflections and diffractions can lead to an error while estimating the channel parameters, such as received power and time of arrival (ToA). In this contribution, by using ray tracing simulations, we present the received power, channel impulse response, mean ToA and delay spread along the UAV trajectory.

The unified asymptotic approach yields an accurate description of chirped dispersive pulse propagation of arbitrary initial width. The saddle points of the phase function appearing in the exact integral expression of the propagated field are central to the application of this approach. In fact, the dynamics of these saddle points are mapped into the characteristics of the propagated field. Therefore, an analysis of the dependence of the saddle points on the input field and medium parameters and on the propagation distance provides unique theoretical insight on the propagated field characteristics. Here, the procedure for investigating this dependence is elaborated and applied to describe the angular frequency dynamics of the propagated field; the regions of up and down chirp of the instantaneous oscillation frequency are also identified.

Our goal is to identify if full channel-state information is needed in order to sufficiently mitigate interferences between the base stations of a wireless mobile backhaul network, which is especially of great importance if the network employs full-duplex operation or terrestrial and satellite links sharing the same spectrum. We analyze and compare the signal-to-interference-and-noise ratio of beam steering and zero-forcing beam steering for a millimeter-wave backhaul network with limited channel-state information, where only the position of the base stations are known while buildings and other possible sources of multipath components are unknown. We use block diagonalization on the transmitter and minimum mean square error beamforming on the receiver as a reference algorithm that utilizes full channel-state information. Numerical analyses based on raytracing in a realistic urban scenario reveal that zero-forcing beam steering outperforms the other algorithms. We conclude that knowing the positions of the backhaul stations obviates the need for expensive channel estimation.

RFID readers serve the obvious role of extracting information from RFID tagged objects. Objects without RFID tags or objects with tags that for some reason are unreadable will not be noted at all when positioned within an RFID reader antenna´s interrogation zone. In this paper, we investigate how UHF RFID reader systems for smart shelf applications could also be used for classification and distance estimation of non RFID tagged objects, if the reader modules provide access to antenna S-parameters. The investigation is performed with an inset fed microstrip antenna where objects of different materials are positioned at different heights above the antenna. It is shown how objects are detected and classified in terms of their materialistic properties through S-parameter analysis and how the distance from the antenna to the object could be estimated.

The structural integrity of composite structures can be monitored and evaluated by using microwave-based techniques. In this paper, five different types of microwave methods that can be used for carbon fibre composites are reviewed. Advantages, limitations and applications of these methods are described. Induction, resonance and time domain reflectometry are suitable for near-field non-contact applications, while thermography and antenna-based methods are advantageous for far-field inspections. Due to the conductive characteristic of carbon fibres, the near-field methods are preferred for better signal penetration over the microwave frequency range.

Conventional wireless power transfer systems consist of a microwave power generator and transmitter located at one place and a microwave power receiver located at a distance. Here we show that wireless power transfer can be realized as a single "distributed" microwave generator with an over-the-air feedback, so that the microwave power is generated directly at the place where the energy needs to be delivered. We demonstrate that the use of this paradigm increases efficiency and dramatically reduces sensitivity to small displacement of the transmitting and receiving antennas, variations in load and power, and possible presence of obstacles between the antennas.

To realize automatic operation of vehicles, it is necessary to install various sensors, e.g., high-quality inter-vehicle cameras. However, currently, conventional harnesses cannot tolerate external noise. Therefore, in this paper, we propose wave hose as a new type of transmission path. We developed a system to transmit microwave power for sensor power supply using a wave hose and simultaneously verified high-speed communication transmission between sensors. We confirmed 1 W of power and an in-pipe transmission of 100 Mbps/ch in this system. We also confirmed that the error vector magnitude (EVM) was less than 5% even in a system with a maximum length of 90 m.

In this work we inspect and validate the backprojection cortical potential imaging (BP-CPI) technique. The BP-CPI is a relatively new tool which estimates highly detailed cortical potential distributions from the smeared measured EEG spatial signals. The testing of this tool includes the study of the BP-CPI sensitivity to real-life interferences and errors, such as electrodes noise, displacement errors, and the number of electrodes. This was done through a series of computer simulations (performed using Sim4Life by ZMT) solving scalp and cortical potential distributions excited by three source configurations. Examining the results in this sensitivity study, it is clear that the BP-CPI technique provides a useful tool for recovering the cortical potential underlying within the subject head.

We developed the nested contour algorithm (NCA) - a segmentation method for mammography images and tested it on a set of 1532 images of 356 women with morphologically proven breast cancer (BC) of various characteristics located on different density background. As a result NCA correctly marked 48 of 52 (92.31 %) star-like lesions, 12 of 14 (85.71 %) architectural distortions, 51 of 58 (87.93 %) lesions with irregular shape and unclear margin, all 18 lobular and round lesions, 17 of 18 (94.4 %) partially visualized lesions, 13 of 18 (72.2 %) asymmetric areas and 7 of 16 (43.8 %) unclearly visible or invisible lesions. Overall sensitivity of NCA in our set was 90.73 % (323 of 356 cases). The mean rate of false-positive marks was 1.3 per image - for ACR А-В mammograms and 1.8 - for ACR C-D mammograms.

We built a prototype of a high resolution surface-based human head model that can be simulated in a reasonable time and evaluated the influence of cerebrospinal fluid (CSF) on field propagation estimates of traveling wave excitation at 297.2 and 400 MHz. Combining neighboring triangular faces located in the same plane into a single one is an approach that achieves simulations of high-resolution human models previously not accessible to tetrahedral-mesh-based solvers. If electrical contact between anatomically connected parts of CSF is correctly considered, CSF was found to partially shield brain tissues from the incident RF field.

We evaluated the performance of several MRI radiofrequency dual-row transmit arrays with a range of overlapping distances, head positions, and tuning conditions. For the geometries, excitation conditions and volume of interest that were investigated, location of the volume of interest in middle of the coil and a small - 10 mm - overlap is preferable. The results provided confirm that with the preferable setup, safety excitation efficiency is practically insensitive to tuning condition, and head position, thus the safety margin can be relative small, allowing shorter scan times.

—This paper presents a low complex and low latency architecture to compute short-time Fourier transform (STFT).This new approach is based on reusing the calculations of the STFT at consecutive time instants. This leads to a significant saving in hardware components with respect to fast Fourier transform based STFTs. In the proposed approach, a N/2 -point FFT is computed, where N is the length of the window and is merged with the FFT of the previous N/2-point to generate an N-point FFT of the overlapped segment. As a result, the proposed STFT architecture presents an excellent trade-off in hardware utilization and latency. The proposed method needs to compute (S+1) number of N/2-point FFTs instead of S number of N-point FFTs, where S is the number of overlapping segments

This paper presents a solution of a well-known problem in electrical energy distribution: the detection of partial discharges in a distribution system also used for communication (such as power control signals). We show the inconveniences of the classical approach (energy thresholding) and we present the results of a new approach, based on the projection of the signals in a multidimensional phase space, followed by a Hough transform-based analysis.

In this paper, an impulse radio ultra-wideband (IR-UWB) radar is used to continuously monitor a resting subject's respiration and heart rates in a noninvasive fashion in order to observe the corresponding health status. These two cardiopulmonary vital signs are inferred based on the processing of recorded waveforms that are collected by the IR-UWB radar, after getting reflected-off the resting subject's body. A novel algorithm that processes the recorded waveforms is proposed to extract these vitals' signals and, accordingly, estimate their rates. This algorithm is comprised of three major parts: i) noise reduction, ii) respiration rate extraction, and iii) heart rate extraction. Furthermore, the algorithm addresses the effects of harmonics and intermodulation between the breathing and heartbeat signals without requiring the implementation of filters. Given an alphabet of datasets that are collected on multiple subjects, numerical results are presented to corroborate the proposed algorithm's accuracy.

In this paper, we present a hypothesis test for the classification of moving targets in the sight of an automotive radar sensor. For this purpose, a statistical model of the relative velocity between a stationary target and the radar sensor has been developed. With respect to the statistical properties a confidence interval is calculated, and targets with relative Radar velocity lying outside this interval are classified as moving targets. Compared to existing algorithms our approach is able to give accurate inference instantaneously without the necessity of filtering the classification results by a tracking algorithm. The proposed algorithm is characterized by an instantaneous classification, a simple parameterization of the model and an automatic calculation of the discriminating threshold.

Pulse-Doppler radar is suitable for target detection and parameter estimation such as range and radial velocity. The signal processing, in this type of radars, is based on matched filter and discrete Fourier transform (DFT). Detection, measurement accuracy and good resolution require the transmission of a train of pulses, where each pulse is usually frequency modulated. In some cases, even few trains of pulses are required. In this paper, we use statistical framework for detection and parameter estimation. In the proposed algorithm, a transmission of a single pulse is required. Moreover, the transmitted pulse is not frequency or phase modulated.

This paper presents the performance of CMOS-SOI TMOS thermal sensor processed in a well-established 1µm technology, operating in air. The TMOS is a micro-machined CMOS transistor, operating at sub-threshold. The thermally isolated floating MOS transistor senses temperature changes induced by either a physical or a chemical phenomenon. The change in temperature modifies the threshold voltage and accordingly the I-V characteristics of the micro-machined transistor. Operation in air, without vacuum packaging, enables low-cost products for a wide range of low-cost commercial mobile applications such as IoT, wearable, smart homes and smartphones.

Here we show a multi-spectral interferometric method to coherently emit and detect multiple terahertz tones on the same antenna equipped silicon chip without the need of external elements. The method consists of exploiting the reciprocal properties of optical, electromagnetic and electrical components of a silicon integrated terahertz harmonic oscillator allowing it to operate as a source and detector in the same time. We name this method retroactive detection or imaging in contrast with traditional active terahertz imaging systems where a distinct source and detector are needed, this retroactive approach eliminate the need of additional terahertz components. By detecting the reflected terahertz waves on a remote target, images of a coin surface are produced at 0.35 THz, 0.7 THz, 1.05 THz and 1.4 THz. The device operates at room temperature in a continuous-wave mode.

This paper compares various circuits allowing on-line temperature measurement and monitoring implemented in CMOS-SOI technology. We start by discussing integrated circuits that generate an accurate output current or voltage proportional to the absolute temperature (PTAT), along with another type of integrated circuits that use the MOSFET threshold voltage to determine the chip local temperature, namely Vt extractor circuits. The accuracy, linearity, stability and calibration problems of the different circuits are discussed and compared with each other in the temperature range of 300K-420K. It is shown that threshold voltage extractor circuits are very appropriate to determine the temperature of low power, analog and mixed-signal designs due to their accuracy, low power consumption and no need of calibration. The circuits have been fabricated using CMOS-SOI 1µm technology, and their accuracy has been experimentally verified by comparing simulated and measured results.

Recently, FIR/MIR detectors based on the vdW heterostructures with the graphene layers (GLs) clad by the widegap barrier layers - GL Infrared Photodetectors (GLIPs) - were proposed and substatiated. In the GLIPs, the GLs serve as photosensitive elements, in which electron-hole pairs are generated due to the interband absorption of FIR or MIR. Due to relatively high probability of the photon absorption in the GLs and low probability of the electron capture into the GLs (in comparison with the traditional quantum-well heterostructures), the GLIPs can exhibit elevated photoconductive gain and responsivity. The doping of the barrier layers, in particularly, the selective doping using the delta layers of donors and acceptors can markedly modify the device band diagram and its characteristics. The doping of the GLs can also affect the GLIP properties. This paper deals with an overview of the GLIPs and related devices.

Design and simulation of a novel photonic low-cost, uncomplicated and cheap tunable sub-millimeter wave receiving system for communication applications are presented. The receiver, capable of operating at 280-300 GHz band is based on low frequency sampling and filtering of narrow band signals embedded with strong white noise in submillimeter spectra using two synchronized low frequency trains (~500 MHz) in order to down-convert and recover the high frequency THz signal under 10dB SNR. The system consists of standard optical devices (lenses, Joint-Transform Correlator and Kerr effect crystal). Before sampling, the received signal (including noise) should be time inverse using time inversion module and accumulated with itself. Using Joint-Transform Correlator, the time manipulated sampling is being correlated and Fourier transformed as a result the 280-300 GHz narrow-band signals can be identified and reconstructed.

Acceleration of in-core LU decomposition by using multiple GPUs in parallel is presented in the paper. Memory limitations of GPUs are overcome by using block LU decomposition, where the entire system matrix is stored in CPU RAM, while only currently processed blocks are stored in GPU VRAM. The presented algorithm for LU decomposition enables utilization of an arbitrary number of GPUs. Judicious load balancing over the GPUs in the most time consuming parts of the block LU decomposition results in high efficiency of the parallelization. The presented results show that a dense MoM matrix with 100 000 complex unknowns in single precision is LU decomposed in less than 9 minutes, on a personal computer equipped with 8 low-cost GTX 680 GPUs.

An advanced hybrid mode-matching (MM) / finite-element (FE) / method-of-moment (MoM) technique is applied for the rigorous and fast CAD and optimization of slot-arrays including layered feeding waveguides. The advantages are high calculation speed, full-wave accuracy, and that antenna optimizations to desired specifications can be directly achieved on the rigorous electromagnetic (EM) level within reasonably short time, while immediately including the complete feed network. Typical calculation times for one optimization iteration are in the order of a couple of seconds up to few hundreds of seconds for large slot arrays on standard quad-core PCs without additional hardware acceleration means. The efficiency and appropriateness of the method for the fast design of slot-arrays is demonstrated at several examples, such as a 900 slot-array with sum- and difference pattern feed-network, a slot-array with layered dielectric cover, a side-slot array with 16 x 22 slots, circularly polarized traveling slot arrays, a travelling wave ridged waveguide slot-array, and substrate integrated waveguide (SIW) slot array antennas for linear and circular polarization.

In this case study we show the dependence of the lead electromagnetic model (LEM) and the RF-induced power deposition (P) on the presence of heterogeneous tissues around of the lead tip. For some lead length, we observed a dramatic non-linear dependence of P and LEM on a small volume of a different tissue surrounding the lead tip, i.e., a fatty pocket. Thus, using LEMs derived in a homogeneous media can result in large systematic errors in predicting P, and consequently the lead tip heating, of AIMDs inside a human body.

The multilevel physical optics (MLPO) algorithm has been adapted to compute radiation patterns of the triple reflector antenna of RATAN-600 radio telescope in new operation modes. These operation modes facilitate tracking of cosmic sources of radiation at arbitrary azimuthal angles in the range of ±30°. The resulting radiation patterns are compared to those obtained via ray tracing analysis.

The Poggio-Miller-Chan-Harrington-Wu-Tsai (PMCHWT) is a widely used integral equation for simulating radiation and scattering from penetrable objects. This formulation, however, is plagued from mesh refinement and low-frequency ill-conditioning. Existing techniques for handling these problems, however, suffer from very low-frequency numerical cancellations or they require the detection of global loops. This work presents a new Calderon-like strategy for the PMCHWT which, leveraging on the quasi-Helmholtz projectors, solves both frequency and refinement ill-conditioning without detecting global loops. Moreover the technique is immune from very low-frequency numerical cancellations. Numerical results confirms all theoretical developments and show the practical impact of the new scheme.

This work is based on the analysis and development of and early alert system for emergency vehicles using Software-Defined Radio (SDR). The system emits radiofrequency signals with frequency modulation over different carriers simultaneously within a delimited range, these signals interfere with the radio receivers of nearby vehicles, alerting other drivers to the presence of the emergency vehicle, thus, allowing them to clear the way which represents a decrease in the time of arrival of the emergency vehicles. In the design phase of this project, an SDR is used to transmit in the frequency range from 88 MHz to 108 MHz and free software platforms (such as GNU Radio and Python) for the development of the communication system and user interface.

This paper presents a new framework for long range Free Space Optical communication (FSO). Motivated by the ever-growing demand for communication in 5G networks, the suggested framework tackles the natural drawbacks of FSO, namely: complicated installation, limited range, size and pricing. The new FSO concept assumes a "best effort" model. It uses a new aiming mechanism based on COTS components. This methodology is mostly suitable for urban FSO links but might also be applicable for both short range (IoT) and long range (satellite) communication. Based on simulations and preliminary field result we expect that such FSO links will be widely used in "best-effort" 5G applications allowing an affordable alternative to fiber optics and standard FSO systems.

A combined sensor and communication network can provide important support for first responders and emergency workers in dangerous environments. The innovation proposed here is use of SDN network control to dynamically accommodate, through an open API, competing resource demands for three distinct but closely associated needs: communication among people, environmental monitoring, and information retrieval. The SDN-controlled configuration realizes the desired flexibility and robustness. This paper outlines the physical and software-defined architecture of a quasi-linear communications-sensing relay network, with an SDN controller, that can be a major asset in emergencies or for work in dangerous environments.

Within 5G future network, ad-hoc or D2D communication is seen as a key enabler to increase coverage and broadband. This work focuses on providing a framework for Mobile Ad-Hoc network (MANET) based Android applications. The framework we developed uses Wi-Fi Direct technology, which would enable connectivity in cases where there is no obtainable access point. In addition, the framework supports Multi-Hop routing and IP addressing among other requirements for proper networking and network management. Our framework expands upon Wi-Fi Direct to support multi-hop data transfer and simultaneous data transfer to more than a single endpoint. The application we developed allows users to request help or specific services from others who are also connected to the application and are in the user's vicinity. The desired services can include anything from requesting assistance in changing a flat tire to emergency situations.

t A very serious concern that has been getting more attention these days due to the Internet of Things - IoT - is the energy saving on battery-powered sensors. There are techniques that try to extend the lifetime of this type of sensor, some related to duty cycles in which the sensor wakes-up periodically and checks if it should take some action, this approach still has a long time of idle listening wasting battery unnecessarily. There are also the techniques known as WUR (wake-up radio) that wake up the radio "on-demand", that is, a device of lower power is responsible for triggering the main radio when it is necessary, thus saving a lot of energy. The use of RFID for this purpose is not new, but has always brought the problem of low reach (solutions reaching not up to 5 meters), the proposed solution aims to find a balanced solution, between energy savings and radio signal reach, that works at the same scenario as IEEE802.11 networks and using technology of active RFID to identify the packets and wake the main device at the appropriate time.

A simple algorithm allows one to follow trajectories of optical radiation which undergoes multiple reflections on a smooth surface described by a net of points, placed at equal distances with respect to the x y co-ordinates and whose z co-ordinates are specified. The x y projected surface is divided in equal area squares which are divided into two triangles. The possible points of intersection of the rays with the surface and the directions of reflection are obtained by geometrical considerations. A series of decisions are made in order to find the first incidence triangle , and the subsequent encountered ones. Some examples showing broken trajectories determined by the algorithm will be given. One is shown by the summary The consideration of diffusing surface will be a further step the study. together with that of polarization of the beam.

This paper considers the original asymptotic method for the analysis of electromagnetic diffraction at electrically thick dielectric layers. The approach is based on combining the small-parameter expansions of the field inside the layer and the ray-tracing outside of the layer. The first two terms of asymptotic expansion are derived. The first term already comprises the correction on layer's curvature. The method is validated and verified by comparison with the corresponding results of solving the Muller boundary integral equation. The limitations of the plane-slab approximation of the curved layer are also discussed.

Modern armed conflicts and terror attacks raise the need for military forces and law enforcing authorities to detect sporadic sources of hostile fire. The usability of fire detection systems in the battlefield strongly depends not only on performance parameters, but also on power consumption and compactness of the system. A CMOS Single Photon Avalanche Diode (SPAD) sensor may be used to sample muzzle fire flash events in the visible range of spectrum from common kinds of weapon, widely used on the modern battlefield. In contrast to regular CMOS Image Sensors, the very high photon detection sensitivity of SPAD practically eliminates readout noise and enables a higher sampling frequency in the Kilohertz range without SNR degradation. A great challenge of an imager for gun muzzle detection is the required fast signal processing. In this work, we shall explore various architectural options for efficient implementation of image classification algorithm for a real-time muzzle flash detection system that requires a high frame rate of the order of 1,000 frames/sec. Then we will use the best approach to provide a real-time solution and evaluate it together with the SPAD sensor to gain further insights.

Due to dynamic development and growing complexity of radio-technical devices, such field as miniaturization appeared. Miniaturization is reduction of device dimensions. This paper presents analysis of the influence dielectric permeability has on effectiveness of branch-line coupler miniaturization. The miniaturization method in this paper consists in use of artificial transmission lines, having smaller longitudinal dimensions than a quarter-wave microstrip transmission line segment. By means of three-dimensional electrodynamic simulation the standard and compact bridge couplers with dielectric permeability of 3, 4.4, 6, 7.2 and operating frequency of 2000 MHz were simulated and their frequency characteristics were obtained. The suggested miniaturization method allowed to reduce the dimensions of bridge couplers by 67.8, 71.15, 70.4, 67% correspondingly as compared to those of standard structures.

Limited locking range in injection locked oscillator based phase shifter (ILPS) is of main concern when used in the local oscillator (LO) path of phased-array systems. This severely limits their use due to failure to lock the free-running oscillator. To overcome this limitation this paper proposes a wide locking range ILPS in the C-band (4 to 8 GHz). The design is aimed to achieve wide locking range at low injection power. Wide locking range is achieved by means of self injection in a CMOS cross-coupled oscillator which reduces oscillator power in a controlled way. The ILPS achieves a locking-range of 3 GHz at 5.3 GHz center frequency under fundamental injection at 0 dBm input power. The ILPS is implemented in a 90-nm RF CMOS process and consumes only 25mW DC power under a 1.8V supply.

We calculated the lead electromagnetic (LEM) model of an external lead with an electrode that contacts human skin at 123.2 MHz and evaluated the influence of the electrode dimension as well as the distance between the lead and the human body on the LEM model using an approximation of the human body by a single tissue flat phantom. Our case study provided strong evidence that at 123.2 MHz there is no worst-case distance between a wire and a human body that maximizes the power deposition for any wire length or electrode width.

This paper describes the procedure of reducing the dimensions of the crossover, implemented on microstrip line segments. The miniaturization procedure is based on substitution of the quarter-wave line segments with a low-pass filter having the same phase shift as the substituted segment. The entire design process was performed in AWR DE 12 three-dimensional electrodynamic simulation software. A common microwave material with dielectric permeability of ε = 4.4 and thickness of h = 1 mm is used. A prototype was manufactured for testing the simulated results. The experimental results demonstrated good compliance with numerical simulation results. Crossover surface area was reduced by 64% as compared to standard design.

We present comparison of higher order basis functions to lower orders, when applied to analysis of 2D electromagnetic structures. To illustrate the performances, several numerical examples have been analyzed. We use method of moments applied to surface integral equations for simulations. The criteria for the comparison are: the accuracy of results, the total simulation time, the total number of unknown coefficients and the memory needed for simulation.

The digital channelized receiver is an efficient way to deal with the problem how to receive signals arriving simultaneously in electronic reconnaissance receiver[1]. An Wideband digital channelized receiver based on weighted overlap-add (WOLA) filterbanks structure is derived from polyphase discrete Fourier transform (PDFT) filter digital channelized receiver. Adaptive double threshold detection method is apply to channel signal detection. Simulation result of the channelized receiver is given. A wideband digital channelized receiver has 2.4Gsps sampling rate and 64 channels channelized with the hardware platform consists of high speed analog-digital converter and high performance field programmable gate arrays. The results show that the design is available and effective.

Aim of this contribution is to illustrate Elettronica's recent development in microwave Transmit/Receive Module technology and present the performance of a C-Ku Band, 8 Channel TX/RX Module for Electronic Warfare Systems. The so-called Blade Module is based on custom Microwave Monolithic Integrated Circuits fabricated in GaAs and GaN technology, designed to perform RF signal conditioning (phase and amplitude control) and front-end functionality (low noise reception, high power transmission, TX/RX commutation). Each channel can provide more than 30dBm saturated output power and can be directly plugged onto an antenna array.

Imaging systems in millimeter waves are required for applications in medicine, communications, homeland security, and space technology. The Glow Discharge Detector (GDD) is a room temperature detector based on a commercial neon indicator lamp, and was previously proven to be very sensitive and inexpensive MMW radiation detector capable of direct and heterodyne radiation detection. In this work the phenomenon of an up-converting of MMW radiation to visual light is used for MMW imaging. The combination of CCD camera and GDD FPA can yield a faster, more sensitive, and very inexpensive MMW and THz camera, eliminating the complexity of the electronic circuits and the internal electronic noise of the GDD. In this work it is shown that by using a unique quasi optical system, 8×8 GDD focal plane array (FPA), and CCD camera, MMW images can be obtained in Real time.

A Reconfigurable and steerable antenna reflector for X band is presented in this work. The realization based on Electromagnetic Band Gap (EBG). A Varactor diode is connected between two adjacent patches of the antenna reflector structure in order to control its capacitance. This approach is known in literature and has been presented in many low frequency studies in the order of several GHz. For higher frequencies such as X-band, the size of the unit cell should be reduced. Thus, the size of the Varactor diode is no longer negligible relative to the total size of the surface causing significant absorbance and scattering. In order to overcome this obstacle, a new unit cell was designed such that the placement of the Varactor diodes is in the back, without deviating from the Lumped element model approximation, thereby enabling low cost electric voltage controlled X-BAND reflector antenna.

In this paper, an adaptive CLEAN method for both clutter mainlobe and sidelobe suppression is proposed.Strong ground clutter may deeply influence low-altitude small targets (LST, e.g. birds, UAV) detection. Existing papers mainly focus on main-lobe clutter suppression, but the side-lobe problems are seldom discussed.So,we proposed a method to solve this question.And it can be described as follows:Firstly, the ideal clutter spectrums are structured using multi-scatterer model. Then, based on the least squares method, the amplitude of each clutter scatterer is optimized to minimize the residual energy of clutter cancellation result. Simulation and experimental data processing results show that the method can effectively suppress both main energy region and the strong Doppler side-lobe of ground clutter, and the minimum detectable speed is superior to the traditional MTI/MTD algorithms.

The new standards for WiFi 802.11ax and Cellular generation 5 require high EVM to enables fast communication in limited BW. Complicated constellation scheme are used to support such high bitrate. High EVM is not easy to achieve in first place, but it is more difficult to keep over extreme condition. Using advanced and simple techniques to calibrate EVM will have a significant improvement of the RFIC performance. The EVM required for the new WiFi 802.11ax and Cellular 5G to ensure high data rate is crossing -40dB. The EVM is a combination of the performance in the transmitter and receiver. It is calculated by the sum of uncorrelated transceiver characteristics. In this paper, I will present the contributors for the EVM, the mathematical analysis and tradeoffs of the fine balanced between them. The second part of the paper, present calibration methods to keep the EVM stable over extreme conditions (temperature and process variation). Some of the parameters need to be controlled by close tracking loop. The "blanket" now is very short. Those calibration loops must be design carefully.

In this paper, an accurate equivalent-circuit model including detailed parasitic parameters of a planar anti-parallel GaAs Schottky diode is proposed for Terahertz application. The 3D electromagnetic model is established according to the actual geometry of diode to extract diode parameters simultaneously. Combined with empirical equivalent circuit model, equivalent circuit model and 3D electromagnetic model, the parameters of diode can be extracted completely and accurately. These models can be used for the design of terahertz circuits.

Epoch is the instant of significant excitations during the production of a speech sequence. Due to time varying nature of the excitation source and the vocal tract system, accurate detection of epochs from the speech remains a challenging area of research. Over the years several algorithms have been proposed for the detection of epochs. Among different techniques proposed in the literature, the zero frequency filtering (ZFF) approach provides better performance for clean and degraded speech. The filter design originally proposed in ZFF has an infinite impulse response (IIR) filter followed by two successive finite impulse response (FIR) filters. Later, the IIR implementation is simplified to finite impulse response(FIR) realization. In this paper, we have designed the efficient architecture for IIR, FIR realization of ZFF and implemented these two realizations on field programmable gate array (FPGA). The performance and characteristics of both FIR and IIR implementation for the task of epoch detection are also compared.

260 GHz waveguide semiconductor switches driven by laser emission are used to cut a continuous-working (CW) microwave emission to series of wave packets. The main advantage of the switches is low distortion to the phases of the packets' high frequency fillings at the output. The phases are linked to each other since the microwave input emission is coherent, e.g. a gyrotron in a phase stabilization regime. Recent studies achieved nanosecond level of switching performance for 260 GHz frequency band and 532 nm laser emission using a semiconductor plate of plain gallium arsenide. Up to now, the switches have been tested with a commutated microwave power of up to 50 mW, limited by the backward-wave oscillator (BWO) test source. The maximum possible power is limited by a WR3 waveguide standard safety value; it is about 20 W (about two times lower than the breakdown value). An obvious solution of increasing smoothly the power level from 50 mW to 20 W using modern gyrotrons faces the problem of measuring errors. Since the rated power for the gyrotrons and their measuring calorimeters is about 1 kW, using them at 20 W produces measurement errors of about 100%, and worse than that, for lower powers. There are no precision commercial measurement devices for frequencies around 300 GHz for the moment. However, laser-power precision measurement devices are easily available. So, we can approximate the Joule microwave heating by substituting it with the appropriate laser heating. For infrared lasers, the heating distribution is like the microwave heating, both their maxima are at the surface, and they both decay inside the semiconductor. Assuming that 70% of the laser power is dissipated at the semiconductor at 1.06 µm, and 30% is reflected, we can convert it to an effective microwave commutated power using the power transmission measurement for a typical switch. The average microwave power transmission coefficient in a wide frequency region is about -0.4 dB. So, the microwave power insertion loss is about 9%. Then, assuming that all the microwave loss is dissipated inside the semiconductor plate, we can say that if the switch withstands a certain laser power, it should withstand a microwave power being 8 times as high. The experiments have confirmed that the switches can produce pulses in the range of at least nine orders of magnitude by duration, from 1 ns to 1 s and even longer, depending on the commutated sub-terahertz power, laser power and operating regime (pulse length and form). The optimum case of the switch depends on the application. We can estimate the values of safe commutated power by substituting the microwave absorption mechanism with the absorption of industrial-standard 1.06 µm laser emission and the power transmission coefficient of the switch. While a WR3 standard waveguide can safely transmit about 20 W of microwave power, estimations show that the sub-terahertz switch should commutate a minimum of about 8 W safely. Although the semiconductor plate has blown in the experiments, the moment of the blow has been recorded, and the minimum withstand time of 15 ms under the maximum possible commutated microwave power has been obtained.

Low power wireless communication is primordial for the realization of devices connected IoT because radio transceivers are one of the biggest sources of power drains. The low power Wake-up Receiver (WUR) is a promising technology that can facilitate this by enabling an on-demand and asynchronous wake-up signal. Although the concept of WUR is not new, only recently it has attracted significant attention from industries due to the development of IOT and energy efficiency that has become a design concern in high performance devices. Energy harvesting is playing an increasingly important role in supplying energy to devices, circuits, and systems. The process captures very small amounts of energy from one or more energy sources, accumulating them, and storing them for later use. On the other side, there is a strong effort on the minimization of energy consumption and dissipation associated to the analog and digital circuitry. Therefore, the strategy of AC-clocked power supply follows this tendency.

In the following summary we represent a multi-polarization antenna system as a radar station. The required volume of the summary doesn't allow us to describe some separate structural and constructive solutions. This research is patent pending. For effective use, modern technology increasingly demands detailed radio scanning capabilities. This is due to substantial growth in technologies relating to massive increases in the mobility of people. One way of meeting such demand is through the use of an electronic analyzer with a sensor in the form of radio antenna. Antennas are of fundamental importance in any radio system. Our antenna can scan the environment in all types of polarization across a continuous monotonically varying spectrum.

The concept of an electrically tuneable inductance based on a transistor circuit is introduced. Even though it incorporates an active circuit, passive, reciprocal behaviour is displayed at the output terminals. The resulting inductance value is tuneable through a variation of the biasing condition, constant for a wide frequency range, and it can be used in either series or parallel circuit configuration. Guidelines for the design of the circuit are presented and used to successfully simulate, build and measure the tuneable inductance. The inductance circuit is a promising approach to closing a long-existing gap, and thereby providing new possibilities of circuit design, e.g., in terms of miniaturisation through integrated circuits. It can prove beneficial for numerous applications, such as broadband matched and tuneable transmission lines, amplifier circuits, oscillators, or filters.

Slot array antennas antennas designed with waveguide technology are considered very efficient antennas. High efficiency is a necessary requirement for airborne radars and airborne weather radars. A slot array antenna requires a power divider. In order to obtain, the required, high efficiency of the antenna, the power dividers are generally designed using waveguide technology. To properly a power divider two conditions are needed, a reactive divider in the H-plane and a non-reactive divider in the E-plane. Generally, a low-profile H-Plane is used to feed the antenna. In this presentation, I will demonstrate the use of an E-Plane power divider to feed the antenna. This power divider has very good isolation at the output ports and good impedance match at the input ports. As a result, is its less sensitive to the connection between the power divider and the antenna. Its primary shortcoming of this design is the 90° phase shift between the two output ports. This phases must be compensated by inserting additional lengths of waveguide to the power divider. The various microwave components and the integration of these components into a complete system was done by using CST-MWS. CST was also used to match the slot array antenna and to correct common mechanical errors which occurred as a result of manufacturing limitations. In summary, CST was used in all phases of the design stages enabling me to build a product which met all the desired requirements.

This paper describes the design and study of the microstrip high-pass filter structure. The suggested filter is implemented on two resonators of same shape, situated on same side of the substrate, and two microstrip lines with serially connected interdigital capacitors on the other side. The filter design and the numerical results were obtained by means of specialized Ansoft HFSS software. Microwave material was selected for the purpose of mathematical simulation and prototype production, with dielectric permeability ε = 4.4 and thickness of h=1.5 mm. Filter cutoff frequency equals to 2000 MHz and working band is 1500 MHz. These results were obtained experimentally using vector network analyzer. The prototype was obtained using standard printed circuit boards production method and has a surface areas of 30 х 30 = 900 мм2.

This paper presents the simulation results of the C-band active vector-sum digitally controlled phase shifter (VSPS) MMIC which is implemented in 0,18 μm RF CMOS technology. VSPS provides discrete phase control in the range from 0° to 360° with 22,5° step achieving 4-bit phase resolution with a 4,5—6,6 dB signal gain. Noise figure is less than 6,5 dB, 1 dB compression ~ -4 dBm. Power consumption is less than 220 mW. The simulation of the phase shifter shows RMS phase error <3° in bandwidth 4—6 GHz with a corresponding amplitude error <1 dB.

A novel direction of arrival (DoA) estimation system based on PCB substrate integrated waveguide (SIW) leaky-wave antenna (LWA) is presented. The proposed scheme which requires only a low-cost passive radiating element is much more cost and power efficient when compared to the traditional DoA estimation techniques based on phased array antennas which also require a high processing gain. One power detector is utilized to estimate the DoA by measuring the received power at the LWA port. The antenna provides high broadside efficiency and low return loss in the frequency range of operation from 50 to 70 GHz. The antenna consists of an array of SIW fed dipoles and can be fabricated through cost-effective PCB processes. An experimental measurement for the proposed DoA estimation technique is presented along with the LWA measured radiation pattern. To the best of the authors' knowledge, this is the first time a SIW LWA is employed for mmWave DoA estimation.

A setup and process has been created to investigate over-the-air mm-wave measurements that are quasi-linear and are at least partially transient in nature including reactions to thermal evolution of the DUT or related to beam position dynamics. Working from a broadband/mm-wave network analyzer platform with a deep memory digitizer and more novel synchronization tools, it was possible to evaluate transient, angle-dependent transmitter compression, cold-start receiver system patterns and transient responses during pattern steps. Measurement uncertainties, for these particular measurements, were largely limited by repeatability on the order of 0.02 dB/0.2 degrees at modest power levels.

A set of GaN technologies are presented including a revised 0.25µm GaN HEMT technology in WIN Semiconductors' NP25 platform. The new improvements to the NP25 GaN HEMT were realized by the optimizing device layout, the fabrication process and the epitaxy enabling improved performance while still maintaining highly reliable operation for X-band applications. Pulse I-V shows low gate-lag and drain-lag ratio of 16% and 6%, respectively. The maximum power-added efficiency (PAE) could be improved from 59.6% to 64.7% at 10GHz. The 0.45µm GaN HEMT technology for L-, C-, and S-band applications has 60.5 % PAE at 2.7 GHz. The 0.15µm GaN HEMT technology for Ka-band applications has PAE 39.6% and power density up to 5.4W/mm.

The paper presents a concept of an indoor navigation system, its structure, mathematical model, positioning algorithm and chosen simulation results. The system can be used to provide for position awareness inside buildings, where GNSS signals are weak or unavailable. The proposed system uses Ultra Wide Band (UWB) modules for Two-Way Time-of-Flight (TW-TOF) ranging and communication. It is composed of several beacons which can be easily deployed around a building of interest and mobile units to be used inside. The beacons are equipped with GNSS receivers and after being deployed around the building they establish their positions and report them in dedicated messages with the use of UWB modules. The mobile terminals use these messages along with their ranging measurements to estimate the user's position. The system can be easily set up and be ready in very short time. It can be especially useful for the military, police and other services.

The accepted method for combining probability distributions is to use the characteristic function of the distribution which is an alternative method for its characterization. This method is extremely cumbersome and leads to expressions that cannot be evaluated in closed form, and in some cases, cannot be evaluated at all. In this paper we show that a simple convolution of the two (or more) distribution functions gives the same result, is much less difficult to calculate, and enables determination of these combinations in almost all cases. We first show that the characteristic and convolution methods give the same result mathematically and then give an example of combining normally-distributed noise and log normally-distributed clutter or atmospheric scintillation, applicable to both radar and communication systems.

This paper describes a radar system for non-destructive testing of foam insulation used on cryogenic fuel tanks in space industry. The radar system consists of a radar and a two-coordinate mechanical scanner which moves the sample in the vicinity of radar antennas to form a synthetic aperture. The radar is based on an Infineon integral transceiver with nominal frequency range from 24 to 24.25 GHz. The component-view of the radar system is given and explained in details, including RF-board, microcontroller, DAC and ADC units, stepper motor drivers, firmware, and user software. Sample radar images obtained with the setup are presented and compared with the radar images of the same sample obtained with a previously created setup in which a vector network analyzer was used to acquire the data.

The modern microwave personnel screening systems use either mechanical scanning by a linear array to form synthetic aperture, or electronic switching of the antennas distributed over a surface. At the signal processing stage it is supposed that the subject holds a stationary pose. This paper describes the new architecture of a microwave screening system in which natural motion of the subject in the vicinity of a linear antenna array is used to form a synthetic aperture. The experimental data are obtained with the setup consisting of a vector network analyzer and mechanical linear drives used to move the antennas in the sampling positions. An RGB-D video sensor captures the depth map of the scene, which is later used to coherently process the radar data. The signal processing algorithm is outlined and accompanied by the radar images of concealed objects obtained in the experiments with a movable mannequin following the stop motion technique.

This paper describes the software and firmware programs developed for interactive control of a frequency-modulated continuous-wave ground-penetrating radar (GPR). The presented radar system is being developed in the framework of the project carried out by European Cooperation in Science and Technology (COST) Action TU1208 devoted to the development of an affordable GPR and introducing it into the educational process. This system combines cheapness with fine operating characteristics and a possibility of switching toward a large number of modulation patterns. The developed software program in Python programming language for the GPR prototype provides graphical user interface allowing simpler and more convenient user interaction with the system. A complementing firmware program was also developed that realizes such control functionalities as selecting the frequency range of the transmitted signal, its period and waveform.

The Synthetic Phased-Array sensors are robust frontier RF wireless technology. They can be employed on mobile platforms for wide-view and high resolution application. Important concerns are the EMI/EMC and the radiation hazards for the deployment of these phased-array sensors.

A novel iterative physical optics (IPO) algorithm for the analysis of scattering from large complex semi-transparent geometries is proposed. Two main modifications of the conventional IPO scheme are introduced to model penetrable scatterers: the geometry is divided into non-overlapping connected homogeneous domains and the fields transmitted between the domains are evaluated, in addition to the conventional reflected field calculations. The algorithm comprises two types of nested iterations: reflection/transmission ("bounce") iterations and iterative shadowing ones. The scheme is applied separately to the bounding surfaces of each domain. The interaction between the domains, through transmission, is accounted for at the conclusion of each bounce iteration. The algorithm is demonstrated to provide a good approximation of an analytical reference solution.

In the Internet of Things (IoT) connecting things (edge systems, routers, hosts) to the Internet makes it possible for them to access all kinds of Web services. However, these devices are resource-limited and suitable selection of communication paths and data retrieval will consume less resources. For this problem a selection of Web services for these devices is needed, and it can be described as single-source many-target shortest path problem. Several researches were done to optimize the architecture of IoT, to fit it to this problem by using different algorithm such as Dijkstra's algorithm to find the shortest path between a source point to a target point. A problem arises when we have to take into consideration other aspects and properties of the end-points (devices), such as the data size, or bandwidth. For this purpose we can see the end point as knapsack items. The knapsack problem is described as follows: For a set of items, we have to determine how many items from every type to include in a collection, so that the total weight is less than or equal to a given limit and the total value is as large as possible. A knapsack item is described as follows: • An item that represents an object of some sort (in our case, an end-point). • The item has at least two attributes (could be more) of weight and value. In our case the weight represents the bandwidth, and the value represents the data size. • The item's attributes are comparable to other items' attributes. There have also been papers about dynamic programming solutions for the knapsack problem, using shortest path problem, with the creation of a knapsack graph such as , but these papers gave a solution to the knapsack problem using the shortest path problem. Another problem arises when a knapsack graph, that its edge weights are non-dependent in the vertices values, is built. For it, a solution was advised in a preliminary research, that takes into consideration all of these aspects. The implementation of this solution to IoT architecture is the main idea of this paper.

The location of irregularities in electrical connections is a well-known problem in many systems (e.g. cars, aircraft, power lines and communication line, to mention just a few). One of the methods used for this purpose is Time Domain Reflectometry (TDR). Basically, it transmits a wave and observes the resulting reflections, much like a Radar. In electrical systems, TDR is used to check interconnects (like power or communication lines) by sending a (relatively) sharp pulse into the interconnect, and observing the reflection (if any). The reflections are caused by irregularities in the interconnect (like shorts or opens). Based on the timing of the reflection (relative to the sent pulse), the location of the irregularity can be determined, and the shape of the reflection provides information about the character of the irregularity (e. g. open or short). Common TDR instruments use very fast pulses (rise time of about 20psec) to enable accurate determination of the location of the irregularity. Such measurements are applicable in testing a system, during maintenance or in repair, when the system is not in operation. However, they cannot be used when the system operates, since the TDR pulses may disturb the normal operation. That is where passive TDR comes in. Passive TDR measurements use the reflections of the regular signals on the bus to detect and locate irregularities in the interconnect. Since passive TDR just monitors the regular signals on the bus, it does not interfere with the operation of the system

Our work describes a Smart Home Framework to be used in Smart Cities. In our days, the rapid growth rate of the elderly population makes it necessary to find smart solutions in order to extend the safe home stay of the individual as much as can be. Our framework allows city designers and developers to focus on building the unique features for the Smart City, improving the simplicity of sensors and application placement in the Smart Home, load-balancing the requests' load between similar operators, reacting quickly to the user needs and creating a greener Smart City.

The basic idea of this paper is the investigation of the performance improvement criteria suitable for multi-channel networks, such as wireless and optical networks. The receiver collisions phenomenon, as the main performance characteristic of the multi-channel networks, is analytically studied. Based on a Poisson statistic model, the average probability of a packet rejection at destination due to the receiver collisions phenomenon, is mathematically derived, considering a finite size of receiver buffer. Also, a closed mathematical formula for the average throughput estimation is analytically proven. Finally, the rejection probability at destination is studied for diverse numbers of stations and data channels

Deploying telecom infrastructure along railway or highway is one Dimensional (1D) and can be made with directional antennas, in order to maximize distance range and minimize interference lateral zones. The need is no longer for a mosaic of big Base-Stations (2D or 3D, with a large number of mobiles), but for a curvilinear chain of small Base-Stations (1D, with 100 to 1000 mobiles each). Using OFDM and enhanced multicarrier waveforms opens the way to combine 2 classes of services from a same comb of base stations; 1) mission critical services for automated devices, which require low bit rate and a double coverage for hot redundancy, 2) multimedia services for smartphones, which require high bit rate and single coverage as long as possible. This paper intends to show how the 2 classes can be covered with an unique chain of small Base-Stations in an iso-frequency arrangement.

Free space optical (FSO) communications has proven to be a solution to the limitations of radio frequency spectrum and data rate. FSO is a promising technology to increase link capacity of non-detectable links to multigigabit per second. However, a beam of light passing through the atmosphere has its phase, amplitude and propagation direction fluctuation along the optical path due to scintillation loss which is a function of atmospheric turbulence. Atmospheric turbulence effect is caused by the randomness of the air refractive index and it depends on the local temperature, pressure and humidity. This is usually quantified by refractive index structure constant (C_n^2) thereby affects the coherence of FSO links. In this paper, specific scintillation loss was estimated based on measurements over a channel. An FSO link with 100Gbps data rate was designed and simulated in an optisystem environment. Evaluation of the effect of turbulence-induced scintillation using bit error rate (BER) analysis on the FSO link was performed. An optical receiver was consequently designed for quality signal integrity.

Our paper presents a novel Speech Recognition Augmented Reality tool for hearing impaired people, based on a case study of a simple Domain Based Speech Recognition approach. Choosing the correct word out of samples with similar acoustic structure is an important challenge in Speech Recognition research. Our scheme improves transcription accuracy in local vocabulary environments, such as in meetings, lectures etc. We developed a tool that combines our approach in an Augmented Reality environment in order to create real-time "live subtitles" using our unique Speech Recognition process. This tool enables hearing impaired and deaf people to see real-time Augmented Reality subtitles' while hearing a talk on a specific subject.

The emergence of the Web 2.0 created new opportunities for knowledge transfer between University - Industry - Society, such as the crowdsourcing phenomenon which has attracted great attention, and has created new possibilities for knowledge transfer that are still being evaluated. However, much of the existing academic research remains unused and unleveraged after being published, never creating the benefits for society that were expected from both the effort that was put in to produce it and the cost that was supported to allow for the research. This paper seeks to present a critical literature review evaluating the existing knowledge transfer mechanisms and pair it with the new possibilities created by Internet of Things to propose a new knowledge and technology transfer framework between University - Industry - Society that better leverages the usefulness of existing published research and applies it to the creation of new innovative solutions, thus creating an alternative knowledge transfer mechanism.

In public key cryptography infrastructure of electronic commerce (E-commerce) use of Rivest, Shamir, and Adleman (RSA) algorithm is very common. With security requirement, the key size of RSA is increasing exponentially. Due to large key size, it is not convenient to use RSA in resource constraint application where computational speed, storage and bandwidth are limited. Elliptic Curve Cryptography (ECC) is the best alternative for the traditional RSA. ECC with less key size provides the same level of security compared to RSA. The most important question in the use of ECC is the selection of the right elliptic curve. There are different types of elliptic curves suggested by various standards. Selection of curve is dependent on the various parameters such as prime field size, the shape of the curve, etc. In this paper, set of elliptic curves recommended by different standards for cryptography are selected, and the selected curves are analysed focusing on the performance and security features. The performance of each curve is measured in terms of computation time. The analysis is performed by considering each curve for implementation of Elliptic Curve Diffie-Hellman (ECDH) algorithm and Elliptic Curve Digital Signature Algorithm (ECDSA). The comparative table of selected curves is prepared considering the computation time taken by each curve to perform various operations when used for the ECC algorithms.

Internet of Things is the next wave of technology in the society where we are visualizing automation in almost everything except the human brain. In this environment, various nodes will collect the data and each node uses a wireless communication technology like Bluetooth, Wireless Fidelity, and, Zigbee for transmitting and receiving the information. Among these wireless communication technologies, Bluetooth Low Energy (BLE) is usually used for the IoT because it is a suitable technology for transmitting and receiving a data using low energy wirelessly. However, there are some attacks described which also are of concern so as to possess added number of satisfied customers. Few attacks like Man in the middle (MITM), channel jamming and battery exhaustion along with some possible countermeasures described by various researchers are delineated in this overview.

Commercial microwave links ("CML"s) are used worldwide to transfer data between cellular towers. These microwave transmissions are affected by the atmospheric medium between the transmitting and receiving towers. By analyzing the properties of the transmitted microwave signal and the communication channel (e.g. - its attenuation, modulation and error-rates) and by fusing additional side-information (e.g. environmental conditions, RADAR maps) it is possible to estimate certain meteorological and environmental conditions (such as rainfall and fog). Modern advances in deep-learning introduce promising new methods of analyzing such modulations and the underlying phenomena that drive them - but most methods are limited in their ability to utilize and fuse side-information and data from different domains. This paper describes initial research and testing of a proposed deep-learning architecture and its implementation on CMLs in Israel - and compares the results with some current state-of-the-art methods.

Data traffic is increasing exponentially, especially on wireless channels as mobile users increasingly make use of online services. Such an increase requires much wider wireless transmission bandwidths. Thus, the carrier wave frequency must be increased to the millimeter-wave (MMW) band (30-300 GHz). This requires the development of new technologies and components for transmitters and receivers operating in this band. In this paper, an experimental demonstration of such MMW wireless channel is presented. The MMW wireless channel is based on a photomixer as transmitter and Schottky barrier diode (SBD) as detector. The carrier frequency was chosen to be 100 GHz. Adding an RF amplifier at the SBD output will enhance the detection, therefore, high data rates in the order of 40 Gb/s can be achieved. Preliminary setup and experimental results are presented in this study.

This paper presents experimental results to support a new method for blind source separation of several biological objects respiration patterns, which were registered remotely by means of a step-frequency continuous-wave bioradar. The method utilizes independent component analysis. Signals registered by a single bioradar at several probing frequencies are used as input data for independent component analysis as they represents the mixtures of the respiration patterns of all observed biological objects. Two experiments with two and three examinees simultaneously observed were carried. The experimental results proved that even in case of biological objects located at the same distance from the radar their respiration patterns can be resolved from the signal recorded by a single multi-frequency bioradar.

Respiratory rate and respiratory rate variability are important indicators of condition of the nervous, cardiovascular, excretory, and respiratory systems. Long-term monitoring of breathing might be useful for health surveillance of seniors and sedentary patients. Non-contact methods, in particular bioradiolocation, can provide essential comfort for permanent monitoring. This paper presents an algorithm for the detection of movement activity periods and breathing cycles on bioradilocation signals for sleeping subjects. The algorithm was validated using data of 27 subjects without sleep-disordered breathing, who underwent a polysomnography study in a sleep laboratory. The results of manual scoring were used as ground truth. Accuracy, specificity and sensitivity for activity period detection are 90%. Accuracy of the peak detection is 97%, and sensitivity is 98%. Our results will be useful for the development of tools for unobtrusive health and sleep monitoring.

This paper reports on the design of multi-band acoustic-wave-resonator-(AWR)-based bandpass filters (BPFs) with enhanced-fractional-bandwidth (FBW) quasi-elliptic-type passbands. They are based on multi-resonant acoustic-wave-lumped-element resonators (AWLRs) that are shaped by the in-parallel cascade of multiple (equal to the desired number of transmission bands) one-port-type AWRs and one lumped-element (LE) resonator. By cascading them in-series through impedance inverters, passbands with increased selectivity and enhanced FBW (i.e., larger than the electromechanical coupling coefficient kt2) can be obtained. In addition, they preserve the high-quality-factor (Q) characteristics of the AWRs. For experimental-demonstration purposes, two UHF-band dual-band BPF prototypes with alternative levels of FBW were designed, manufactured, and measured. They exhibited two transmission bands centered at 418 MHz and 434 MHz, respectively, with FBWs of 1-3kt2 and minimum in-band insertion loss (IL) in the range of 0.5-1.25 dB (i.e., effective Q >10,000).

In this paper, a High Frequency Model of a Npath Band Pass Filter (BPF) is presented and analyzed for easier and faster design cycle. The analysis of Npath filters is quite difficult due to its complex operation. The simulation of such circuit must include very high number of harmonics, taking the simulation long time to converge. The Npath model allows us to reduce simulation time (up to 100 times). The ratio between the lowest and the highest impedance was improved from 15 to 33 using the model on TSMC 65nm RFIC process, improving the rejection of the BPF.

This paper addresses noise modeling of transfer substrate indium phosphide double hetero bipolar transistors (InP DHBTs). Transistors with an emitter area of 0.8×6 µm2 (single-finger) and 2×0.8×6 µm2 (double-finger) are measured and simulated. It turns out that the correlation of shot-noise sources is negligible for these devices, although it was found in earlier works to be essential to describe GaAs HBT noise behavior. As a result, the work provides the basis for reliable extrapolation of noise performance beyond the frequency range provided by standard noise measurement equipment.

We present an inductor model that takes into account current density variation in all three dimensions of the trace conductor, particularly targeted for high performance passives on low-loss substrates. By generating multivariate polynomial surrogate models of the model parameters, accurate prediction of inductance and quality factor up to 5 GHz is achieved when loss is dominated by metal losses and conductor current density is highly non-uniform in all dimensions. Compared to full-wave simulation, model-predicted inductance is within 12% error and predicted quality factor within 13% error for 96-98% of geometries. The model predicts frequency-dependent inductance and quality factor in the order of 100 ms.

In this paper, the integrated N-Path-Filter-Based circulator is thoroughly analyzed. Simplified linear time invariant (LTI) circuit models are introduced in order to perform the analysis. These models are then verified by comparison to the complex linear periodic time varying (LPTV) model of the circulator. Exploiting the insight acquired from the simplified models, a new and improved topology for the integrated circulator is proposed. The simulated sum of Tx-to-Ant insertion losses and NF are less than 1dB at 100MHz and less than 2dB at 2GHz. These results are significantly better than the previously reported state-of-the-art integrated circulator.

A compact coplanar waveguide (CPW) fed reconfigurable antenna with pattern diversity using multi-port excitation is designed. The basic antenna consists of a rectangular patch of size 5mmx4mm which is fed by four ports independently. By exciting the patch with each individual port, the direction of the radiation pattern changes by 900. With the use of CPW feed technique, a very wide impedance bandwidth of around 9GHz covering the whole 18GHz-27GHz (K-band) is achieved. The proposed antenna can be used for different satellite communication applications like earth exploration, radio navigation and location, mobile satellite communications which comes under K-band. The measured return loss and pattern characteristic results are in good agreement with simulated ones.

A relatively flat X-band dual-horn antenna is presented. The antenna is based on an input waveguide, a folded horn divider, and two E-plane coupled horns. The height of the antenna is 2 wavelengths, the matching level is SWR = 1.8, and the gain is 20 dB at 10 GHz

In this paper, we present two wearable antenna designs, for Bluetooth and cellular communication. Both antennas made on jeans substrate using conductive garment. Four modules, each of them includes both antennas, installed on a human body. Also, an antenna for hearing aids device is designed and simulated. The S parameters of antennas system, gain and SAR (Specific Absorption Rate) were calculated.

We present an innovative antenna of new type characterized by a very wide bandwidth, and exhibits advantages over both dipole and monopole. It is based on the MB antenna in which source currents are properly enforced such that the in phase currents are fed to a single conductive radiating element. The currents fed to MB antenna's radiating element are made in-phase by means of a delay line (180-degree phase shifter) introduced in one of the source leads. The MB antenna has been recently developed as a single radiating element (like a monopole), and no ground plane (like a dipole). The MB antenna is a multiband antenna radiating at odd-harmonics of its fundamental frequency determined by the delay line used in its feed circuit. The MB antenna can be implemented by the PCB of mobile handsets, acting as the radiating element. Experimental results confirming the validity and the performance of the proposed antenna are presented.

Phased array and MIMO (Multiple Input Multiple Output) radar systems are being developed with greater number of channels to achieve more flexibility, speed and range. Each channel contains either an ADC (Analog to Digital Converter) - for a receiver channel - or a DAC (Digital to Analog Converter) - for a transmission channel. This type of system has a number of challenges:- The high speed data interface needs to be optimum and efficient; All channels should be easily synchronised; The down conversion element adds to system cost and complexity; Beam-forming time delay circuits also add complexity. This paper describes a new ADC which addresses each of these issues. Some initial results from the ADC are presented.

This paper presents the design, analysis and testing of a PCIe 4.0 PBERT clock source module. The design included two PLL synthesizer modules and a controller. The first module outputs a clean 200MHz clock for an FPGA, while the second outputs a 16GHz data-rate clock. The 16GHz clock can be output very clean (less than 10mUI) or modulated to add random or deterministic jitter as desired. To obtain the above, this paper includes an analysis of the phase noise contributors and design of a loop filter to achieve the lowest possible jitter. The design is implemented without the need for a custom designed ASIC and using only readily available parts. To further reduce cost, the design was implemented on FR-4.

This preliminary paper presents a measurement scenario for the indirect identification of long term memory kernel of a two-path memory behavioral model. The measurement principle is based on the use of a regular VNA setup and is applied here for the characterization and modeling of a Down-converter chain. It has been experimentally demonstrated that this measurement principle allows accurate model identification by performing a simple set of measurements. Extracted model proves the ability to provide a good prediction for complex communication signals.

In many cases, S parameters measured by network analyzer are exported as datasets for post analysis and processing of the measurement results with a circuit simulator, MATLAB procedures and even Excel spreadsheet. This approach improves production efficiency, as the measurement equipment is usually very expensive and requires experienced operators. The algorithm often used to extract Deviation from Linear Phase (DFLP) is a Linear Regression algorithm. In most programs this algorithm is provided as an internal function, but it is not the proper algorithm for DFLP since it provides a linear phase function that has the least average error from the investigated phase function, while a proper algorithm for DFLP should provide a linear function that has the least absolute maximum error from the investigated phase function. This discrepancy could (and does) lead to over specifications of products and to rejection of good products. In this paper, an easy and practical way of providing the correct DFLP by using the internal Linear Regression Function is presented.

This paper presents the measurement and analysis of local oscillator isolation in an analog frontend based on monolithic microwave integrated circuits (MMICs) at a carrier frequency of 300 GHz. The transmit-receive wireless system uses a single balanced resistive mixer with in-phase and quadrature channels that provides a very good isolation of the local oscillator. The dependency of the isolation on the baseband input is presented. The isolation obtained when a signal is transmitted only on the in-phase channel is higher than in the case of the signal transmitted on the quadrature channel. The paper presents the measurement method and a theoretical analysis which confirms the experimental observations.

This communication deals with the relations between structural and electromagnetic (EM) properties of carbon foams. EM properties were investigated over a wide frequency range, from 20 Hz up to 250 THz. The bulk density is the main parameter controlling the EM behaviour up to 50 GHz, as no change was found by varying other structural parameters such as cell size or interconnectivity in such frequency range. For cellular foams, transmission and reflection tend to be negligible in the infrared region, and behave like black bodies. However, reticulated foams present non-negligible transmission that increase with cell size. Resonance phenomena were observed for reticulated foams between about 0.2 and 3 THz. It was shown that the frequencies corresponding to the minima and maxima of transmission of these resonance peaks can be determined by considering the fundamental mode TE10 of a rectangular waveguide whose larger dimension is the average cell diameter.

A research discipline - nanoelectromagnetics - is introduced as a synthesis of macroscopic electrodynamics and microscopic theory of electronic properties of different nanostructures. The approach is exemplified by carbon nanotubes and graphene-based structures, and briefly touches upon other nanocarbon forms. Both theoretical and experimental results are discussed.

The electromagnetic (EM) properties of polymer composites based on multiwall carbon nanotubes (MWCNT) were investigated and compared in the microwave (26-37 GHz) and terahertz (0.1-1 THz) frequency ranges. Two various types of matrixes as well as two different technologies of composites preparation were used to produce materials with equal MWCNT content. It was experimentally proved, that MWCNT-based composites with concentration nanofiller above percolation threshold are good candidates for effective microwave absorbers. Nevertheless, for further practical broadband applications it is necessary to predict and control agglomerates contribution in polymer composite. In the present communication, we demonstrate that microwave and terahertz EM responses are very useful in estimating a quality of MWCNT distribution within the polymer matrix.

A quantum antenna can shape spatial entanglement of emitted photons originating from entangled states of antennas emitters. In contrast to the classical antenna, the quantum antenna can shape the second and higher order correlations without affecting amplitudes of the field. The shape and directivity of the correlations can be optimized using techniques of quantum state inference. Positive and negative correlated twin-photon, and multi-photon entangled states can be produced from the same antenna for different initial states of emitters.

Today, electronics are implemented on rigid substrates. However, many objects in daily-life are not rigid - they are bendable, stretchable and even foldable. Examples are paper, tapes, our body, our skin and textiles. Until today there is a big gap between electronics and bendable daily-life items. Concerning this matter, the DFG priority program FFlexCom aims at paving the way for a novel research area: Wireless communication systems fully integrated on an ultra-thin, bendable and flexible piece of plastic or paper. The program encompasses 13 projects led by 25 professors. With flexibility we refer to bendability, foldability, and stretchability. In the last years the speed of flexible devices has massively been improved. However, to enable functional flexible systems and operation frequencies up to the sub-GHz range, the speed of flexible devices must still be increased by several orders of magnitude requiring novel system and circuit architectures, component concepts, technologies and materials.

This paper presents an On-Off-Keying (OOK) modulator for a flexible and wearable wireless transmitter implemented in an amorphous-Indium-Gallium-Zinc-Oxide (a-IGZO) TFT technology. The circuit consists of a three-stage ring oscillator for the carrier and an output driver with an OOK modulation switch. In order to maximize the operation frequency, we use 2 µm-long nMOS transistors in the circuit design. The proposed OOK modulator is fabricated on a polyimide flexible substrate, and characterized with 3-to-5 V supply voltages. The circuit operates from the lowest supply voltage of 3 V, while the highest measured oscillation frequency is 3.76 MHz at 5 V VDD. Although the schematic is simple and straight forward, the equivalent modulation depth ranges from 61.3 % to 78.2 %, which can be detected with an existing flexible a-IGZO AM/OOK receiver. The power consumptions for 3 V and 5 V supply voltages are 2.15 mW and 6.77 mW, respectively.

The state-of-the art technology for high power RF applications is based on GaN HEMT (High Electron Mobility Transistor) devices. Due to the extremely high power, GaN devices are susceptible to high increase in channel temperature which subsequently causes degradation both in performance and reliability. It is widely known that the self heating phenomenon is one of the main problems facing the GaN technology. In order to cope with the self heating effect, many measures have been taken to dissipate the heat and many more are planned. For example, one of the main considerations in growing GaN on SiC substrates has been the high thermal conductivity of SiC. However, applying current thermal management technology enables only partial utilization of the technology. The roadmap to employ GaN high power amplifiers in high frequency and CW mode consists of developing more sophisticated technology, which will ultimately evolve into near-junction active cooling. Our activities include characterization of the self heating phenomenon in GaN devices, both through calculations and through measurements and implementing new technologies into our products. Materials for passive cooling have been introduced both as heat spreaders/carriers and die attach materials. The effects of contact thermal resistance have been investigated with and without thermal interface materials. An activity in package level active cooling has been initiated. Finally, research has been done on using integrated thin diamond films atop the GaN devices for near-junction cooling, passive in the nearer future, and possibly active in the farther future.

Memcomputing is a novel computing paradigm we have introduced that employs memory (time non-locality) to both store and process information on the same physical location. Memory may be due to any physical property of the system, whether spin, charge or atomic configuration. Digital, hence scalable, memcomputing machines can be designed to solve complex problems very efficiently both in hardware and in software. We will introduce their mathematical definition and provide several examples of complex problems solved using self-organizing logic gates, namely logic gates that organize dynamically to satisfy their logical propositions. We will also show that the power of these machines originates from topological features, instantons, that connect critical points in the phase space with different indexes. Having a topological character, digital memcomputing machines are robust against noise and disorder.

In this paper we describe the architecture and design of a non-blocking 4×4 switch matrix module for mm-wave satellite communications, where flexible signal distribution becomes increasingly relevant. Following the successful on-orbit verification of a blocking 4×4 switch matrix for a reconfigurable Ka-band input multiplexer aboard the planned German Heinrich Hertz mission, the non-blocking switch matrix module offers relevant advantages in terms of signal routing and total power consumption. The non-blocking switch matrix utilizes hybrid-integrated precision laser-trimmed Wilkinson power splitters and low microwave-loss absorptive transistor-based SPST-switches.

This paper considers formulation and optimization of channel capacity of magnetic communication systems through various types of mediums, subjected to an overall power constraint. Following a parametric investigation of the induced electromotive force, the optimal operation frequency is derived. Maximization of channel capacity is obtained by a modified "Water filling" algorithm, which provides the optimized power allocation along the spectra. The results are compared to constant power spectral densities with optimized bandwidth, symmetric or asymmetric around the optimal frequency. It is shown that for a given system, the bandwidth and its spectral location, are the dominant parameters that determine the channel capacity, whereas the exact shape of the power allocation has less significance. Also, an upper-frequency limit is required to prevent overestimation of capacity in dielectric media conditions. Resonance circuits are compared to circuits without capacitors, showing similar results regarding capacity but with narrower bandwidth for the resonance circuits.

This paper presents an integrated software/hardware platform for verifying the multiuser multiple-input multiple-output (MU-MIMO) transmission according to LTE transmission mode 9 (TM9) spec. Corresponding MIMO vector signal generator and analyzer (VSG/VSA) software is developed, which can be run on computer with interface to an instrument-based software defined radio (IB-SDR) platform. In so doing, the signal-to-leakage-noise-ratio (SLNR) criterion is utilized at the VSG side to design the precoder matrices for sending different data streams to multiple users. Then we demonstrate a 4x4 MIMO VSG/VSA experiment for a 4-layer multiuser beamforming case. The TM9 testing result in terms of beampattern and error vector magnitude (EVM) can be confirmed by Keysight's 89600 LTE VSA. Hence, the IB-SDR approach provides a cost effective and flexible alternative for MIMO system testing.

This paper demonstrates two-dimensional digital predistortion scheme employing vector-piecewise-decomposition (2D-VPD) on concurrent noncontiguous signals. Simulation results show piecewise predistorter achieves noise floor of -60dBc, an on-par performance with 4 nonlinearity order terms compared to 7 on non-piecewise predistorter. Optimal selection of the piecewise decomposition improved predistortion residual floor by 10dB. The suggested predistorter enables complexity reduction on both learning and implementation, which result in cost and power efficient design for WiFi, mobile and IoT solutions.

Wireless Power Transfer (WPT) enables a new platform for electronic integration and system partitioning. In industrial and commercial applications, the ability to remove wired interconnect not only frees the power device from a physical connection, it can also enable improved performance. Key to supporting today's smart systems, is the need for communication and control in addition to power. In this work we present a WPT powered tail light that is able to be fully sealed to prevent any moisture or debris intrusion, while receiving full power for lighting. Communication is provided using LIN protocol through a Binary-Phase-Shift-Key (BPSK) Master and a load-modulated Slave.