Keywords: Sensing, Radar, Terrestrial and Spaced-Based Communications including Wireless Communications, Industry, Medicine, and E-Health
Abstract: The millimeter-wave radar is a 79-GHz FMCW imaging radar with 16-ch receiving units for digital beamforming (DBF) processing. With the application of digital beam-forming technology (DBF), antenna beam scanning becomes unnecessary, making it possible to process the image in every transmission repetition period. With high-speed image processor using FPGA, it is possible to increase the frame rate of 2-dimensional radar image up to 10kHz.

In security applications, the radar observes people walking, tracks them for several seconds or more, and captures flash reflection from suspicious objects. To extract the radar signal of a moving object, coherently integrated image and incoherently integrated image are compared. The coherent and incoherent integrals of a stationary object are almost the same, but the coherent integration is smaller for a moving object because of phase change. This made it possible to separate moving objects from stationary objects.

The displacement of the observation target is measured from the phase change of the two-dimensional radar image. In order to measure vibrations, it is necessary to observe the target at a flame rate two times higher than the vibration frequency. According to the analysis, the displacement measurement accuracy is determined by the SN of the radar image. A 79 GHz radar can measure a displacement of 5 microns at SN 30 dB. The actual measurement data agrees with the analysis results, indicating that it has a measurement accuracy of 5 microns.

Keywords: Radar, Terrestrial and Spaced-Based Communications including Wireless Communications, Sensing, Radar, RCS Measurements, and Processing
Abstract: In order to improve the throughput of security inspections, rapid scanning devices are developed in the world[1, 2]. The authors are developing a new type of scanning device which has the function to take the radar image and passive image from the radiation from the human body[3]. This paper describes the development of the radar imaging function using the dual-frequency bands to improve the range resolution of the radar within the authorized radio location band. The range resolution of the radar is explained and an imaging result to bond the dual-band measurement data is analyzed.

Keywords: Microwave, Millimeter-Wave, and THz Systems, Radar, RCS Measurements, and Processing, Sensing
Abstract: Airport runway foreign debris (FOD) detection system automatically detect small debris on the airport runway. The primary sensor of the developed FOD detection system is 90 GHz band millimeter-wave radar. The clutter of the runway may cause the degradation of the detection performance. In this paper, fundamental characteristics of the runway clutter is evaluated at airport experiments. Firstly, the specifications of the radar are explained. Then, the measurement conditions at the Airport is discussed. The measured maximum radar cross section is around -49 dBsm. In addition, the different clutter characteristics, changed with the center of the runway, are observed due to the runway cross section gradient.

Keywords: Radar, RCS Measurements, and Processing, Near-Field and Far-Field Measurements, Scattering and Diffraction Measurements
Abstract: We investigate a foreign object debris detection system using millimeter-wave radar technology for the airport's safe operation. The frequency band used is allocated for passive operations such as earth exploration satellites and radio astronomy and radar applications(active service). The size of the plane is more than 10,000 times larger than the radar signal wavelength, so it is not practical to calculate the radar scattering cross section by electromagnetic field analysis using the finite element method. Therefore, it is necessary to study the scattering characteristics of the radio waves emitted from the radar reflected by an aircraft. We calculated the Bistatic RCS of a plane using the Shooting and Bouncing Rays(SBR) method, which is suitable for electromagnetic field analysis with a large scale of analysis. For example, in large aircraft B747, the maximum RCS in the skyward direction is less than 50 dBsm.

Keywords: Radar, Terrestrial and Spaced-Based Communications including Wireless Communications, Radar, RCS Measurements, and Processing, Sensors
Abstract: This paper reports an experimental result on a secondary radar for detection of hidden pedestrians. A transponder carried by a pedestrian responds to a radio-wave transmitted from a car. The distance between the transponder and the car can be measured by a dual-frequency CW radar scheme or an oversampling-based configuration.

The number of traffic accidents in Japan has been decreasing over the past few decades. One of the reasons for this is the development of sensing technologies such as millimeter-wave radar and lidar using visible and infrared light, which can detect obstacles on the road and avoid collisions. These technologies have been designed using the line-of-sight (LoS) method. In order to further reduce traffic accidents in the future, it would be meaningful to develop radar systems that can detect pedestrians and other obstacles at intersections with no line of sight in dense urban areas and residential areas. Other methods of detecting obstacles in non-line-of-sight (NLoS) have been explored, such as vehicle-to-vehicle communication systems and communication between vehicles and radars installed on roads with poor visibility. However, it is difficult to install these systems at all poor visibility intersections due to their high installation cost. To solve this problem, we have proposed a secondary radar consisting of a simple transponder carried by a pedestrian emits a radio wave in response to a radio wave from an on-board transmitter. The latency inside the transponder can be minimized by using the simple transponder consisting of a frequency doubler. The response signal is phase-locked with the radio-wave from the onboard transmitter, so that the response signal can be stably analyzed by coherent detection. We have demonstrated NLoS pedestrian detection by using dual-frequency CW radar scheme and oversampling-based signal processing. Due to scattering and diffraction at the corner, the ranging performance would be degraded. But, the pedestrian transponder can be successfully detected by the onboard transmitter. The radar would distinguish which side the pedestrian located at.

Keywords: Radar, RCS Measurements, and Processing, Non-Destructive and Evaluations Testing, Inverse & Imaging Methods and Techniques
Abstract: The typical electromagnetic inverse scattering problems (ISPs) are aimed at retrieving the geometric parameters (such as the shape, position) and constitutive parameters (such as the permittivity, conductivity) of the unknown target from the knowledge of measured scattered data with both amplitude and phase information (which is denoted as FD-ISPs). Electromagnetic ISPs have wide application in the fields of microwave remote sensing, non-destructive detection, medical imaging, underground resource detection, implanted device detecting, through-wall radar [1]. To solve FD-ISPs, many traditional nonlinear iterative inversion methods have been proposed, such as Distorted Born iterative method (DBIM), Newton-typed method, and CSI/SOM-typed algorithms. However, accurate phase measurement is extremely difficult in practice for two reasons: 1) it is generally known that the accuracy of phase measurements cannot be guaranteed, especially for operating frequencies approaching the millimeter-wave band and beyond, so equipment for measuring phase is exceedingly expensive and the measurement procedure is sophisticated. 2) the phase information is more susceptible to noise pollution than the amplitude information, which leads to deviations in the measured data. Therefore, it is very significant to develop inversion models and methods to solve the ISPs with only the amplitude data or phaseless data (denoted as the PD-ISPs) [2]. Compared to the FD-ISPs, the PD-ISPs counter more serious nonlinearity and ill-posedness owing to the loss of the phase information. In this paper, two kinds of fast inversion methods are proposed to solve the PD-ISPs, i.e., single step method and two-step inversion method. The conventional non-linear inversion methods via the nee-typed contraction integral equation are introduced. And then the learning-assisted methods are also used for the electromagnetic inversion with amplitude data only. Owing to good nonlinear representation ability of neural networks, the PD-ISPs can be well solved efficiently via learning-assisted inversion. Numerical examples verify that the proposed learning-assisted methods has good inversion performance, generalization ability and good robustness,which can fulfill the inve

Keywords: Inverse & Imaging Methods and Techniques, Non-Destructive and Evaluations Testing, Sensing
Abstract: This paper presents the bi-directional processing between radar and tomography method, as the range points migration (RPM) and the contrast source inversion (CSI) schemes, for microwave non-destructive testing applications. The numerical and experimental tests demonstrate that the proposed schemes upgrades the reconstruction accuracy in both dielectric profile and the ROI.

Keywords: Inverse & Imaging Methods and Techniques, Scattering and Diffraction Measurements
Abstract: Iterative phase retrieval from noisy Fourier intensity data continues to be an important and challenging inverse problem with diverse applications. Iterative phase retrieval algorithms typically use measured intensity constraint in the Fourier domain and desired constraints such as support, positivity or sparsity in the object domain. The application of object domain constraints on the solution is however somewhat disconnected from the Fourier domain constraint. We show that phase-less Fourier intensity data contains information about complexity of the desired object and this information can be utilized to advantage in the object domain to obtain artifact-free phase solutions. While we will illustrate working of the complexity guidance methodology with the hybrid input-output (HIO) algorithm, the complexity guidance approach may potentially be used with any phase retrieval algorithm.

Keywords: Near-Field and Far-Field Measurements, Antenna Measurements in Controlled and Non-Controlled Environments, Electromagnetic Measurement Methods and Techniques
Abstract: In this paper, the problem of planar array antenna diagnostics from near-field measurements is addressed by the Back transformation method and the Matrix Method. Reconstruction results obtained by collecting the field with the non uniform sampling proposed in [3] are compared to the ones obtained by the classical one half wavelength sampling. It is shown that in order to solve an array diagnostic problem, the non uniform sampling strategy is more efficient than one half wavelength sampling.

Keywords: Inverse & Imaging Methods and Techniques
Abstract: The problem of sparse signal recovery from quadratic cross-correlation measurements is considered. Compared to the signal recovery problem that uses linear data, the unknown here is a matrix, X, formed by the cross correlations of a K-dimensional vector that is the unknown of the linear problem. Solving for X creates a bottleneck as the number of unknowns grows now quadratically in K. To solve this problem efficiently a dimension reduction approach is proposed in which the contribution of the off-diagonal terms of the matrix X to the data is treated as noise and is absorbed using the Noise Collector [Moscoso et al, The noise collector for sparse recovery in high dimensions, PNAS 117 (2020)]. With this approach, we recover the unknown X by solving a convex linear problem whose cost is similar to the one that uses linear measurements.

Keywords: Electromagnetic Measurement Methods and Techniques, Inverse & Imaging Methods and Techniques, Industry, Medicine, and E-Health
Abstract: This paper proposes a novel “multi-shot” calibration technique that reduces imaging microwave reconstructions artifacts, compensating for uncontrolled variations during the measuring process and later propagated in the inversion. The calibration combines different consecutive sets of measured data with simulated ones in a post-processing stage, providing benefits without the need for additional experimental reference calibrations. The proposed scheme is tested experimentally in a non-trivial scenario. A microwave scanner images an early-stage hemorrhagic stroke in the left parietal lobe, applying a differential imaging algorithm based on the truncated singular value decomposition. Though, the proposed mechanisms can be used for other microwave imaging devices. The results reveal that the calibration procedure improves the quality of the retrieved images compared to the non-calibrated approach, cleaning the images and making the interpretation of imaged contrast variation easier.

Keywords: Microwave, Millimeter-Wave, and THz Systems, Inverse & Imaging Methods and Techniques, Industry, Medicine, and E-Health
Abstract: Microwave imaging (MWI) is a modality recently proposed as a way to provide real-time imaging of liver tumor ablation. In this contribution, the advancements and challenges in the development of such a medical device are reviewed and discussed.

Keywords: Inverse & Imaging Methods and Techniques, Industry, Medicine, and E-Health
Abstract: In the past decade, a number of microwave imaging prototypes have completed the preliminary experimental stages and reached clinical trials. These prototypes are categorized into those using microwave tomography and those using radar-based techniques. Among radar-based prototypes, MammoWave from UBT Srl has recently been undergoing clinical trials in multiple hospitals. A thorough calibration and characterization procedure for any hardware machine is of utmost importance in order to maximise its accuracy and effectiveness. In this paper, we will present results from MammoWave characterization procedure, examining its symmetry and repeatability. MammoWave uses only one transmitting and one receiving antenna operating in 1-9 GHz frequency band (with 5 MHz sampling). The antennas are installed at the same height, in free space and rotate around the azimuth collecting the microwave signals from different angular positions. S21 signals are recorded in a multi-bistatic fashion, such that for each transmitting position the receiving antenna is moved to measure at 80 receiving points (every 4.5°). We have 15 transmitting positions, displaced in 5 sections centred at 0°, 72°, 144°, 216°, and 288°. To proceed with MammoWave characterization, we first performed a set of measurements with an empty machine (i.e., no phantom); next we prepared a homogenous phantom and performed a set of measurements. Finally, phantoms with inclusions were prepared, where the inclusion was placed in different positions, with measurements being repeated for each location of the inclusion. Moreover, in this paper we also present the preliminary outcome of MammoWave clinical trial results on 102 breasts from 64 patients, with distinctive radiological findings and densities. The patients undergoing the trial also went through a conventional exam, and the respective radiologist review was used as a gold standard. The review classified the breasts as those without radiologist findings (NF) and those with radiologist findings (WF), i.e. with lesions that could be benign or malignant. After performing the microwave exam, we calculated several image features to allow distinction between NF and WF breasts, achieving a sensitivity of 88%.

Keywords: Microwave, Millimeter-Wave, and THz Systems, Modeling, simulations, and predictions of Measurements in Realistic Environments, Inverse & Imaging Methods and Techniques
Abstract: In this paper, a method for the definition of a sensor fidelity zone for a microwave breast imaging system is presented. The sensor fidelity zone is specified as a binary indicator of the pixels in the imaging scene, for which the data of each sensor should be used for imaging. Due to the high level of power loss of the electromagnetic waves when propagating through the breast tissues, but also due to the presence of the breast in very close vicinity to the microwave sensor array, the scattered field data, as received by each sensor of the imaging system, is expected to carry exploitable information on a portion only of the imaging scene. The a priori specification, and input of this partitioning of the imaging scene to the imaging algorithm, can lead to considerable mitigation of artifacts and quality enhancement of the microwave breast image.

Keywords: Inverse & Imaging Methods and Techniques, Sensing, Industry, Medicine, and E-Health
Abstract: Microwave Imaging (MWI) is an emerging technique, which can potentially supplement other well-assessed imaging modalities in medical diagnostics. However, it entails solving a very challenging non-linear inverse problem.

Radar imaging approaches drastically simplify the matter but return images that are more like indicator functions that tend to highlight strong inhomogeneities as hot spots. Hence, they are mainly suited for detection purposes.

Even under the simplified linear framework, the are some issues to be dealt with. One concerns the tissue frequency dispersion (which are unknown or known with a considerable degree of uncertainty) as well as by the antenna frequency response, which is hard to predict because it the close proximity set-up. To cope with these problems, "incoherent" approaches can be employed, which showed that the performance remains stable by using different types of antennas, although they responses were not taken into account . Another crucial ingredient is the clutter (due to antenna’s internal reflection, the skin interface, etc.) that generally overwhelms the relatively weak signal coming from the targets. To this end, we developed a hybrid clutter removal method and checked the approach for 3D multi-modal breast phantoms. In particular, clutter mitigation strategy is based on three steps. First, an entropy based time gating is used to remove antenna internal reflections and skin contributions; second, a subspace projection method is used to reduce contributions coming from the bulk of the scattering structure within which the weak target is embedded; finally, a second entropy based procedure is exploited to select, among all the available measurement positions, the ones which mainly are contributed by the target signal. Stimulated by encouraging results obtained in our previous research, we have developed a complete radar system (electronics, antenna, mechanical support, etc.).

In this contribution we will give a quick review of the incoherent methods and the clutter mitigation procedure. Also the developed prototype microwave system, which exploits incoherent methods, will be described.

Keywords: Sensors, Near-Field and Far-Field Measurements, Non-Destructive and Evaluations Testing
Abstract: A dual probe system has been developed for conducting experiments at frequencies near 3 GHz. The system contains a pair of square loops and each of them is loaded by a cubic resonator with high dielectric constant to enhance its field intensity, resulting in a sensitivity about 30 dB greater than other near-field probes. The high sensitivity allows the probe detecting field disturbances further away compared to other probes, thereby possibly enabling strong penetration through a lossy medium. Therefore, this probe system potentially finds application in medical imaging.

Keywords: Sensors, Industry, Medicine, and E-Health, Non-Destructive and Evaluations Testing
Abstract: It is shown by simulation that a sharp image of a lossy object with a step change in permittivity can be obtained using a negative-refractive-index (NRI) lens at 3 GHz. The object is illuminated by a TEM wave and the reflections are focused onto the image plane. The fields on the image plane are sampled and analyzed. This opens up the possibility of applying the NRI lens in medical imaging.

Keywords: Industry, Medicine, and E-Health, Antenna Measurements in Controlled and Non-Controlled Environments, Modeling, simulations, and predictions of Measurements in Realistic Environments
Abstract: This paper presents a compact super-wideband (SWB) monopole patch antenna with an elliptical ground plane for microwave imaging with a focus on medical applications for non-invasive detection of cancerous tissues. The proposed antenna exhibits a 10 dB bandwidth over the frequency range of 2.45-25 GHz with a peak gain of 12 dBi and a stable omnidirectional radiation pattern. The proposed antenna is applied to a microwave imaging system to detect lung cancer using a signal frequency of 3.6 GHz. The lung tissue is represented as a simulated phantom with five layers. Malignant tumors of 5-15 mm radius are also simulated within the lung phantom. The S-parameter results show good potential of the proposed antenna for lung cancer detection, as cancerous tissues are shown to cause differentiable reflection and transmission performances.

Keywords: Industry, Medicine, and E-Health, Sensors, Microwave, Millimeter-Wave, and THz Systems
Abstract: This paper discusses a method to improve the resolution of microwave biomedical sensors. In particular, the specific focus is on microwave sensors dealing with the problem of continuous blood glucose monitoring, in which the shift of the resonance frequency is tied to the variation of the glucose concentration. Usually, since the quality factor of such sensors is usually relatively low, it follows that the resonance peak is not very pointed. Furthermore, the sensor response is gathered over a finite and countable set of frequencies, and hence the actual resonance peak may not be properly caught. To overcome these drawbacks, a procedure based on a super-resolution method is presented, in order to accurately detect the resonance frequency. The algorithm is first evaluated on a synthetic function simulating the response of a real resonant sensor; subsequently, measured data collected by a patch resonant antenna which is immersed into a water glucose solution with different level of glucose concentrations are also considered.

Keywords: Sensing, Non-Destructive and Evaluations Testing, Microwave, Millimeter-Wave, and THz Systems
Abstract: IF-conversion of W-band wireless signals using an antenna-coupled electrode electro-optic modulator and photonic technique is reported. Clear spectrum and spectrogram were obtained with a S/N ratio over 15 dB. This modulator is applicable for the wireless signal detection and calibration of W-band radars and imagers.

Keywords: Microwave, Millimeter-Wave, and THz Systems, Radar, RCS Measurements, and Processing, Radar, Terrestrial and Spaced-Based Communications including Wireless Communications
Abstract: High precision and small-object-detectable radar systems are highly demanded in non-destructive imaging for concealed material detection as well as collision avoidance systems for autonomous vehicles. In the latter case, the precision radar system is also utilized as a radar altimeter. Generally, unmanned aerial vehicles require these altimeters for precise localization and navigation. Moreover, the radio-wave-based altimeter is also useful under degraded visual environment conditions, for example, when multi-copters roll up sands. However, conventional S-, C-, and Ku-band radars have a wavelength longer than 1 cm, and thus, small obstacles and objects which avoid safe landing cannot be detected. In this sense, millimeter-wave and terahertz-wave radars are promising solutions for the detection of small objects. Moreover, the broad bandwidths in the terahertz-wave bands realize a high range resolution.

For radar signal generation, an optical frequency comb generated by an optical modulation technique is useful from the viewpoint of high order multiplication as well as precise waveform generation. Higher-order sideband components by overdriven optical modulator provide a frequency-separated optical two-tone signal with a combination of optical band-elimination and band-pass filters. After photodetection, an optical heterodyne system provides the terahertz signals converted from the optical two-tone signal into the terahertz signal at the frequency, corresponding to the frequency separation between optical components. When the optical modulator was driven by a frequency-modulated continuous-wave (FM-CW) signal at a center frequency of 12 GHz with a chirp bandwidth of 1.5 GHz, a 300-GHz FM-CW signal with the bandwidth of 12 GHz can be obtained with +/-8th-order harmonic components of the optical frequency comb. This terahertz-wave optical signal can be easily delivered by a low-loss optical fiber (0.2 dB/km typically) and be split by an optical coupler. This radio over fiber (RoF) technique is available for the terahertz-wave distributed radar system.

We would like to discuss the distributed radar system based on these techniques and possible applications such as a radar altimeter in the talk.

Keywords: Radar, RCS Measurements, and Processing, Scattering and Diffraction Measurements, Radar, Terrestrial and Spaced-Based Communications including Wireless Communications
Abstract: In this contribution a ground penetrating radar demonstrator setup is discussed with a multi-bistatic antenna configuration for fundamental studies on object detection and localization. Broadband measurements from 100 MHz to 10 GHz with a network analyzer are conducted and analyzed both in the frequency and time domain. Measurement results are discussed with respects to several fundamental issues regarding object detection and identification, such as spatial and amplitude resolution, dynamic range and measurement time. In particular, the effect of antenna coupling and its effect on the measurement results are investigated. Finally, educational aspects in high frequency engineering are discussed considering the measurement setup itself as a complex system that requires expertise in a lot of other interdisciplinary fields, e. g. signal theory, filtering, and data analysis.

Keywords: Inverse & Imaging Methods and Techniques, Antenna Measurements in Controlled and Non-Controlled Environments, Microwave, Millimeter-Wave, and THz Systems
Abstract: An approach for antenna array diagnostics is presented in this paper. The developed procedure is based on the solution of the underlying inverse problem by means of a Lebesgue-space inversion technique, which has been found to be quite effective in retrieving small and isolated defects without the need of strictly enforcing sparsity constraints. The proposed technique has been preliminarily validated by means of numerical simulations involving simple array structures, showing good capabilities in identifying defective regions.

Keywords: Inverse & Imaging Methods and Techniques
Abstract: Optics and radio-frequency electromagnetics now both need to work with many distinct channels for communications and sensing. A common framework, based on singular-value decomposition, clarifies the number of degrees of freedom and the true nature of orthogonal communications modes, and resolves many paradoxes. This approach leads to fundamental results in optics and electromagnetics, and maps well to recent advances in complex optical interferometric circuits for handling multi-mode fields.

Keywords: Industry, Medicine, and E-Health, Modeling, simulations, and predictions of Measurements in Realistic Environments, Sensing
Abstract: Temperature monitoring during thermal therapies is used to regulate the amount of heat distributed to the cancerous tissue and therefore improve the clinical outcome of the oncological treatment. For the development of a hybrid hyperthermia system with non-invasive temperature monitoring by means of ultra-wideband (UWB) imaging, the optimal configuration of sensing antennas and heating applicators has to be investigated. In this paper we present the results of numerical simulations of several possible antenna arrangements, which are then validated by experiments with the radar system. The performance of each channel configuration was analyzed and benefits for the different clinical scenarios were specified.

Keywords: Inverse & Imaging Methods and Techniques, Electromagnetic Measurement Methods and Techniques, Modeling, simulations, and predictions of Measurements in Realistic Environments
Abstract: This work examines the impact of prior information (or “initial guess”) for calibrating a microwave tomography system for brain stroke detection and differentiation, using a multi-layered, anatomically complex head phantom. The imaging algorithm applies the distorted Born iterative method (DBIM) combined with the two-step iterative shrinkage thresholding(TwIST) method. The initial guess for the algorithm is based on two models with different available information: one filled with the dielectric properties of average brain tissue, and one with a more accurate representation of the true head phantom. Our initial results demonstrate that the addition of thin head tissue layers (such as CSF) in the forward model is not critical for the successful reconstruction of the target’s dielectric properties. As expected, however, we achieve more accurate results with the multi-layer initial guess in challenging cases such as detecting an ischemic stroke-like target in the presence of a six-layers Zubal head phantom.

Keywords: Industry, Medicine, and E-Health, Sensing, Inverse & Imaging Methods and Techniques
Abstract: The design of a multistatic ultra-wideband (UWB) microwave radar imaging system for breast cancer detection is presented in this paper. Based on pseudo-noise code (M-sequence) technology, this multiple-input-multiple-output (MIMO) system includes 24 antennas and records data from 128 channels. Furthermore, it realizes complete rotation of the antenna array around the breast, which allows several options of clutter removal and differential imaging, respectively. The system underwent a first feasibility study on volunteers at University Hospital Jena. The procedure of examination and first experiences are described in this paper.

Keywords: Inverse & Imaging Methods and Techniques, Non-Destructive and Evaluations Testing, Microwave, Millimeter-Wave, and THz Systems
Abstract: In this paper, a microwave inverse-scattering technique based on the inversion of S-parameter measurements by means of a nonlinear method in variable-exponent Lebesgue spaces is presented. A two-dimensional finite-element formulation is adopted to model the measurement setup accurately. The approach has been preliminarily validated using numerically simulated data, showing promising outcomes.

Keywords: Microwave, Millimeter-Wave, and THz Systems, Scattering and Diffraction Measurements, Non-Destructive and Evaluations Testing
Abstract: To avoid economic losses due to fruit diseases, farmers need to control quality before harvesting and thus before the fruit reaches the consumer. In this paper, we present a proof of concept for damages detection in fruit with a minimum number of measurement points. By using the Grey Wolf Optimizer, the number of measurement points drops from 12701 to 106 and we obtained 93% and 100% of accuracy. We also investigated the influence of sensitivity of the measurement system on the classifier.

Keywords: Microwave, Millimeter-Wave, and THz Systems, Electromagnetic Measurement Methods and Techniques, Near-Field and Far-Field Measurements
Abstract: In this paper, the design, implementation and validation of a mm-Wave multipurpose system to perform antenna measurements, active antenna array calibration, material characterization, and radome testing is presented. The proposed system was developed based on a modular architecture that shares one set of instrumentation and two sets of antenna probes for five different operation modes without the need of changing the setup. This novel configuration enables a flexible, unique, and cost-effective solution for mm-Wave applications that operate from 75 GHz to 110 GHz. The proposed scanner includes a visual interface that guarantees autonomous operation permitting accurate measurements in all operational modes. The scanner was implemented and validated using different mm-Wave components, providing highly accurate measurements for each mode. Measured results for near-field, far-field, material and radome tests present excellent agreement with simulation results

Keywords: Modeling, simulations, and predictions of Measurements in Realistic Environments, Microwave, Millimeter-Wave, and THz Systems, Radar, Terrestrial and Spaced-Based Communications including Wireless Communications
Abstract: A method for compactly deploying and beam steering antennas on CubeSats is proposed and validated. The motorized rods increase the resolution of steering compared to industry-standard single-pivot gimbals, while their deployment mechanism eases the stringent size requirements in space. The very high gain and reconfigurability that can be provided through this design can be utilized to realize space networks in the Terahertz domain, where a low power output and high spreading loss can otherwise cripple the communication distance.

Keywords: Microwave, Millimeter-Wave, and THz Systems
Abstract: Continuous wave (CW) millimeter-wave radars have gained the interest from industry for accurate sub-wavelength distance measurements. In particular, the six-port radar architecture presents advantages such as high resolution combined with low-power consumption and low-cost implementation in the millimeter-wave regime. In this effort, a new test platform based on fully automated piezo-electric nano-positioning stages that simulates moving targets in XYZ directions with centimeter range combined with nanometer resolution is described. The test platform is crucial to yield performance metrics in terms of repeatability, sensitivity and accuracy. Preliminary experimental results considering a WR15 six-port CW radar designed and realized for harsh environment operation are presented to validate the approach proposed.

Keywords: Electromagnetic Measurement Methods and Techniques
Abstract: Sparse L0 optimization arise in many signal and image processing techniques. The L0 term is non-continuous non-convex and leads to nondeterministic (NP) hard problems. We review some approaches to tackle the L2-L0 optimization problem both in the penalization and in the constrained form. Among examples of inverse problems, we focus on fluorescent super-resolution microscopy by Single Molecule Localisation Microscopy and MA-TIRF (Multi-Angle Total Internal Reflection Fluorescence) reconstruction. We finally show how acquisition of a sequence of images allows to leverage fluctuations of molecules for super resolution by sparse optimization and how these data can be used in a generative adversarial network built to solve the inverse reconstruction problem with a data term, which considers the statistics of the observations, learned by the network.

Keywords: Modeling, simulations, and predictions of Measurements in Realistic Environments, Microwave, Millimeter-Wave, and THz Systems, Radar, Terrestrial and Spaced-Based Communications including Wireless Communications
Abstract: This paper presents the characterization of the propagation channel at 60 GHz in a meeting room. This characterization was done using measurements and simulations. From measurements we provide the angular received power and the path loss using a vector network analyzer (VNA) operating on 2 GHz bandwidth. In simulations, we use ray tracing technique trying to respect the same measurements conditions, in order to obtain comparable results. Finally, we compare the measurement and simulation results in direct orientation (DO) and in best indirect orientation (BIO). This will be useful for designing beamforming techniques for future millimeter communication systems.

Keywords: Radar, Terrestrial and Spaced-Based Communications including Wireless Communications, Sensors
Abstract: In the present paper, we address the performance of the secrecy outage probability (SOP) and secrecy capacity (SC) of the reconfigurable intelligent surface (RIS) assisted communications. Particularly, we minimize the signal-to-noise ratios (SNRs) of the eavesdropper link in place of maximizing the legitimate link. A simple heuristic algorithm is proposed to attain the optimal phase shifts that minimize the SNR. Numerical results are provided to verify the effectiveness of the proposed solution compared with the random phase-shifts.

Keywords: Modeling, simulations, and predictions of Measurements in Realistic Environments
Abstract: The coming years should see an ever increasing density of wirelessly connected devices as the Internet of Things (IoT) emerges. To cope with the expected lifetime requirements of devices, signaling has to be minimized and it is difficult to envision a scheduled channel access protocol. Grant free access are consequently an option to be explored - it is nowadays an option chosen by LoRa and SigFox. To meet the expected high number of devices, non orthogonal multiple access schemes are to be implemented. And to face the growing application demand, several solutions will be available implying a high heterogeneity in both devices and networks (architectures and protocols). These facts will result in highly uncoordinated transmissions with a large number of devices sharing the same frequency band. It has been shown in theory and experimentally that the generated interference will, in such situations, exhibit an impulsive nature. IoT and 5G networks need to take into account the interference statistical properties, for instance to design robust receivers.

Keywords: Radar, Terrestrial and Spaced-Based Communications including Wireless Communications, Modeling, simulations, and predictions of Measurements in Realistic Environments
Abstract: In this paper, we design a communication and coding strategy for Lossy Forwarding (LF) systems with multiple relay nodes or helpers based on Low-Density Parity-check Codes (LDPC) with message transfer decoding applied on a Tanner-graph that maps the network. The system performance is investigated under the cases of a fixed number of helpers, and a random multiple shifted-Poisson distributed helpers for orthogonal Rayleigh fading channels. All the practical results will be also compared and validated with respect to theoretical outage probabilities.

Keywords: Antenna Measurements in Controlled and Non-Controlled Environments
Abstract: This paper presents the experimental measurement of antenna diversity with a 868MHz gateway. Different scenario including indoor and outdoor are performed and diversity gain is computed. Results show a diversity gain ranging from 3 to 4 dB for half the packets received.

Keywords: Antenna Measurements in Controlled and Non-Controlled Environments
Abstract: This paper presents an embedded device based on the Semtech SX1280 IC, which supports LoRa technology at 2.4GHz. The system is integrated into a circularly polarized (CP) antenna with 30 mm in diameter and 8.2 mm in height. The proposal hardware is measured and compared to the actual Ebyte E28 module that using the linear polarized (LP) antenna as a printed monopole.

Keywords: Antenna Measurements in Controlled and Non-Controlled Environments
Abstract: This paper presents the effect of the polarization of antennas used in Ultra-Wideband systems for positioning applications. Measurements have been conducted using the DecaWave DWM1000 module and its antennas on both the transmitter (tag) and receiver (anchor) sides. The received power with the anchor-tag distance were measured with two configurations, co-polarization and cross-polarization of the two antennas. Results in real indoor scenario show that RSSI is strongly affected by the polarization sense for distance lower than 10m. For larger distance, the polarization mismatch has a negligible effect.

Keywords: Antenna Measurements in Controlled and Non-Controlled Environments
Abstract: This paper presents the deployment of a Low Power Wide Area Network (LPWAN) in Danang city. The different steps from the preliminary test to the full network deployment are reported. Interference issues with mobile phone network is also discussed. The different method and material used to assess network performances are also reported.

Keywords: Radar, Terrestrial and Spaced-Based Communications including Wireless Communications
Abstract: In this paper, a slot-based pattern reconfigurable antenna is presented. The antenna can provide an omnidirectional and a directive pattern, while keeping a good impedance matching and radiation efficiency over the 2.4 GHz band.

Keywords: Radar, Terrestrial and Spaced-Based Communications including Wireless Communications, Sensors, Modeling, simulations, and predictions of Measurements in Realistic Environments
Abstract: An Internet of Things (IoT) terminal supporting four frequency bands is presented. The dimension of the terminal is 300x30x0.8 mm^3. It integrates a LoRa 868 MHz antenna, a dual-band GNSS antenna (used for Galileo navigation), and a LoRa 2.4 GHz Inverted-F Antenna (IFA) realized on an FR4 substrate. This kind of terminal can be manufactured directly through a printed circuit board (PCB) technology, which makes it low-cost and suitable for IoT applications.

Keywords: Radar, Terrestrial and Spaced-Based Communications including Wireless Communications, Sensors, Modeling, simulations, and predictions of Measurements in Realistic Environments
Abstract: A novel pattern reconfigurable antenna geometry that alters between four possible states in order to collect RF energy around it is introduced in this paper. Planar Yagi-Uda elements are combined in a single patch antenna to beam steer at different angles with a large coverage over the azimuth plane. The antenna operates in a large range of frequencies and resonates at a frequency of 2.44 GHz with a maximum dimension of 0.55 lambda while having a front-to-back ratio greater than 10 dB. The simulated results show that it has a peak gain of 3.05 dBi. The proposed antenna design has been adapted to be integrated into IoT applications.

Keywords: Radar, Terrestrial and Spaced-Based Communications including Wireless Communications, Sensors, Modeling, simulations, and predictions of Measurements in Realistic Environments
Abstract: A pattern reconfigurable parasitic element antenna system is proposed to operate in LoRa 868 MHz band. As part of a sensor for real-time air quality monitoring in urban spaces, the antenna system is composed of a microstrip balun-fed dipole and two parallel parasitic replicas used to reconfigure the radiation pattern through the use of switches.

Keywords: Radar, RCS Measurements, and Processing
Abstract: Classical calibration procedures for radars make use of metallic trihedrals offering high radar cross section (RCS) with limited sensitivity to angular positioning. A specific shape of the trihedral plates is able to flatten further the angular response. So do also Luneberg lenses, having the further interest to be more easily integrated onboard a flying platform for calibrating surface-based radars at long range or training tracking radar operators. But achieving large RCS with such passive devices may face size limitations, which can be overcome through an active set-up of a receive antenna, an amplifier and a transmit antenna. The equivalent RCS can be easily controlled by the gain of the amplifying chain. Despite limitations coming from antenna coupling and non-linearity of the amplifier, a wide range of operation can be achieved with such an active device; it becomes even wider when adding capability for amplitude and/or phase modulation.

Keywords: Electromagnetic Measurement Methods and Techniques, Scattering and Diffraction Measurements, Radar, RCS Measurements, and Processing
Abstract: A thin coding metasurface was produced with 8 x 8 random configurations formed of two elements, encoded as element “0” and element “1”, with a phase difference equals to 180±30° in a broad frequency band from 28 to 40 GHz. An optimal coding metasurface allowed to reduce the monostatic and bistatic Radar Cross Section (RCS) below -10 dB from 28 to 40 GHz when compared to a perfect electric conductor (PEC) plate with same size. The coupling effect produced between the elements has been reduced. The optimal random coding metasurface was designed by using an efficient method of minimization called "pattern search" with the help of planar array theory, and simulated by means of the CST Microwave Studio software.

Keywords: Industry, Medicine, and E-Health
Abstract: Continuous Wave (CW) microwave radars have attracted the interest from the research community for contactless, low-power and non-ionizing detection of human respiratory and heart frequencies. Optimum radar architecture design and optimization require the identification of systematic and non-systematic errors in both guided and radiating microwave paths of the system. In this effort, an heterodyne CW radar built up with reference measurement instrument is used to accurately identify sources of errors. The measurement campaign is very instructive, providing a guide to improve CW radar architectures implementation.

Keywords: Scattering and Diffraction Measurements, Radar, RCS Measurements, and Processing, Electromagnetic Measurement Methods and Techniques
Abstract: By applying the scale invariance rule, scattering measurements of analogs using the microwave analogy technique can be obtained for different types of objects. Our analogs have centimeter sizes and aim to represent various types of protoplanetary dust particles. The analogs are fabricated by 3D printing, allowing to control their structure, shape, and permittivity. Measurements and simulations were done at frequencies ranging between 3 and 18 GHz. The purpose of this abstract is to show how it is possible to obtain the phase function and degree of linear polarization based on our bistatic scattering measurements. The measurements are compared with our finite element simulation code. Measurements were made in the anechoic chamber of “CCRM" in Marseille. Bistatic scattering measurements were done with separate emitter and receiver antennas. Incident transmission and scattered transmission are obtained. Both transmissions are then transformed into an incident and a total field, following accurate calibration, to yield the final scattering field of the analog particle, via a complex subtraction. Two scattering zones were measured and simulated. The so-called "forward scattering" from scattering angles of θ =130° to -130° and the "backward scattering" from θ = 120° to 168°. On top of moving the antennas, the analog is also rotated. In total, each analog was measured between 72 and 108 different orientations to mimic the behavior of randomly oriented objects. Measurements were repeated with both antennas set to the same polarization state, vertical and horizontal, to calculate the perpendicular and parallel elements of the Jones matrix or Sinclair matrix. Based on these two elements, the phase function and degree of linear polarization were calculated.The phase function is defined as the averaged intensity of the scattered field at multiple orientations through different scattering angles as P=(|S1|²+|S2|²). Another important scattering property that can be calculated is the degree of linear polarization which is defined as DOP= (|S1|²-|S2|²)/(|S1|²+|S2|²). Different results of fractal aggregates at different frequencies are presented herein.