ABSTRACT. In the near future one of the main challenging tasks is the wireless powering of a multitude of ubiquitous devices and machines, to allow truly perpetual wireless-powered communication (WPC). This talk addresses possible RF architectures of transmitting and receiving sides for battery-less wireless sensor network scenarios. Multi-domain design techniques, combining EM theory and numerical simulation with nonlinear circuit design, demonstrate successful system implementations. Novel design examples will be discussed, such as tags, incorporating UWB signaling passively generated, for high precision localization (centimeter-level) and their relevant exploitation for predictive maintenance in industrial plants. Smart solutions for energy-on-demand focusing will be presented. Design challenges for both the transmitting and receiving subsystems are introdced together with performance achievements in real scenarios. BIO: Alessandra Costanzo is full Professor at Alma Mater Studiorum, Università di Bologna, Italy, since 2018 where she leads the RF and wireless lab. She is currently involved in research activities dedicated to design entire wireless power transmission systems, based on the combination of EM and nonlinear numerical techniques, adopting both far-field and near-field solutions, for several power levels and operating frequencies. She is VP for publication of the IEEE RFID Council. Chair of the Wireless power Transfer Conference & Expo (WPTCE) steering committee past AE of the IEEE Transaction on MTT, past-chair of MTT-25. She will be the chair of EuMC2022, Milan, ITALY. She is IEEE Fellow.

ABSTRACT. A number of applications in the millimeter-wave region of the spectrum require improved performance of solid-state devices, e.g. increased output power levels and high level of integration. This talk overviews GaN MMIC circuits designed in several millimeter-wave GaN processes, including the Qorvo GaN15 and GaN09, WIN Semiconductors NP15 and HRL 40-nm T3 process. Several Ka-band GaN PAs for operation with signals of varying output power will be presented, followed by a detailed discussion of the design and characterization of multistage power amplifiers (PAs) with varying levels of on-chip power combining for operation at W-band. Additional circuits that pave the path to a full integrated front end will be presented, including VCOs, frequency doublers, mixers, phase shifters, LNAs and switches, all implemented in the HRL 40-nm process. Finally, some heterogeneous integration techniques that are currently in development for millimeter-wave frequencies will be overviewed.

Short Bio

Zoya Popovic is a Distinguished Professor and the Lockheed Martin Endowed Chair of Electrical Engineering at the University of Colorado. She obtained her Dipl.Ing. degree at the University of Belgrade, Serbia, and her Ph.D. at Caltech. She has graduated over 65 PhD students and currently advises 18 graduate students in various areas of high-frequency electronics and microwave engineering. She is a Fellow of the IEEE and the recipient of two IEEE MTT Microwave Prizes for best journal papers, the White House NSF Presidential Faculty Fellow award, the URSI Issac Koga Gold Medal, the ASEE/HP Terman Medal and the German Humboldt Research Award. She was named IEEE MTT Distinguished Educator in 2013 and a Distinguished Research Lecturer of the University of Colorado in 2016. She was elected as Member of the National Academy of Engineering in 2022. She has a husband physicist and three daughters who can all solder.

ABSTRACT. Generation of proper source/load pull impedances for a selected active device is essential to design an RF power amplifier for optimum gain and power added efficiency. As they are obtained, these impedances may not be realizable network functions over the desired frequency band to yield the input and the output matching networks for the amplifier. Therefore, in this paper, we introduce a useful method to test if the generated source and load pull data are realizable. The proposed technique is employed to test the given source and load pull impedance data obtained from the 45W-GaN power transistor of Wolfspeed CG2H40045 over 0.8-3.8 GHz bandwidth.

ABSTRACT. In this paper, Carlin’s Real Frequency Line segment technique (RF-LST) is generalized to cover both single and double matching problems. The new method is called the “Unified Real Frequency-Line Segment Solutions to Broadband Matching Problems (U-RFT)”. U-RFT is an excellent numerical tool to assess the gain-bandwidth limitation for the given complex terminations of the matching problem. An example is presented to exhibit the utilization of the newly proposed U-RFT method to design a two-stage power amplifier using the Wolfspeed GaN transistors of CMPA0530002S and CG2H40035 which yields 35 Watts output power with 78% efficiency.

ABSTRACT. In this paper, A Metamaterial bowtie antenna, operating at 28 GHz, is designed based on the theory of Characteristic Mode Analysis (CMA). We use the theory of characteristic modes to investigate the bowtie antenna's behavior, and to properly place the MTM unit cells to improve the bandwidth and the gain. According to the simulation results, the gain varies from 6.12 dB to 8.74 dB and the bandwidth increases from 11.28% to 20.75%. This design is suitable for millimeter-wave 5G applications.

ABSTRACT. In this paper, we present a UHF-RFID-based noninvasive sensor to measure the concentration of ethanol in water using the volume fraction of liquids in mixture solutions. The sensing system operates at the UHF band (860-928 MHz). The percentage of ethanol in water changes the dielectric properties of the solution and consequently changes the sensitivity of the RFID tag antenna. The operating principle of this sensor is based on the permittivity change of a solution by the change of concentration of the ethanol in water. Our flexible RFID-Tag sensor is a low-cost alternative to identify the possible sensitivity of tag changes and is able to detect the variation to 25% of the ethanol in 9 ml of deionized water (DI-Water). This solution is suitable for avoiding toxic mixtures of counterfeit ethanol solutions. The experimental setup is small, quick, contactless, and inexpensive. The results presented for ethanol solutions with small concentrations ranging from 25% to 100% in a small tube container.

ABSTRACT. in this paper we present a patch antenna operating at the 28 GHz frequency for 5G applications, this antenna offers a wide band of the order of 2GHz to sufficiently cover the 28 GHz band and has a considerable gain which reaches 7.18 dB. The simulations carried out gave satisfactory results.

ABSTRACT. This paper presents a design of a superdirective array of 3 monopoles antennas with radiation pattern reconfigurable in ISM band. It is principally based on Uzkov’s theory, who define the possibility to obtain a high directivity in order of N*N in a desired direction by linearly associating a large number of N radiators closely spaced. Since we calculated specific currents excitation in magnitude and phase to obtain a superdirectivity reconfigurable for desired directions, we design this array antennas by exciting one monopole by a unit current and loaded the others two by impedances Znload determined from uzkov’s theory. This impedances are each other directly connected to its pin diode which allow to swicth in a desired direction without any mutual coupling between monopoles and cover all 360 deg of azimutal plane. This array antennas, efficient at 96%, presents approximately similar results in all 360 deg of azimtal plane with a reconfigurable directivity in order of 5.2dB and a Back lobe of -14dB with an Half Power Beam of around 120 deg in every direction.

ABSTRACT. The present work was performed to expand the knowledge on human RF-EMF exposure, considering the use of mm-wave spectrum in mobile communication applications, due to the deployment of 5th generation (5G) networks. The mobile antenna was modelled based on the 5G innovation technologies (i.e., mm-Wave bands, beamforming capability and high gain), resulting in a phased array antenna with 8 elements at the working frequency of 27 GHz. Three different skin layers models were simulated, to spot differences in the peaks of absorbed power density averaged over 4 cm2, following the ICNIRP guidelines. The simulations were implemented using the Sim4Life platform, simulating not only the presence of a mobile phone user, but also of a person passing nearby, who could be hit by the phased array antenna main beam. This work underlined that the absorbed power density peaks were greatly underestimated using the homogeneous skin model, respect to the multi-layers skin models. Moreover, for the person passing nearby, we found slightly higher exposure levels than those assessed for the mobile phone user. Lastly, in all the examined cases, the limits indicated by the ICNIRP guidelines were well respected.

ABSTRACT. A novel technology that has been spreading in recent years is the wearable one. It has wide variety of applications, from the medical field to the military one. From the point of view of the human exposure, the wearable devices are interesting because the antenna is posed on the human body, directly involving the human tissues in the exposure. Moreover, since the antenna is integrated in the human clothes, it is very likely that it could modify its position. For this reason, in this work the exposure assessment has been performed by means of stochastic dosimetry, in order to evaluate the effect of the variation of the antenna positions on the exposure level. In this work, it was obtained a surrogate model that makes possible the exposure assessment in 1000 different positions of the antenna, with a computational cost significantly lower than the deterministic dosimetry and describing the exposure with an error below the 3%.

ABSTRACT. In this work, near field exposure of the military crew to a vehicular antenna was investigated in a realistic scenario. The aim was to deepen the knowledge of induced electric (E-)field and SAR inside the human body (i.e. Duke, ViP, v.3) when it is standing partially outside the vehicle, in close proximity of the radiating antenna. Dosimetric results obtained at 16 MHz showed that, while the intensity of the radiated electromagnetic field exceeds guidelines reference limits, the E-field and SAR values induced inside the body remain well below the safety limits.

ABSTRACT. A full wave method developed for the analysis of lossy dielectric disks is applied to the evaluation of the field induced in a Petri dish exposed in a reverberation chamber. The rich scattering environment can be modeled by means of a plane wave expansion, which is usually approximated taking into account only a few waves. The proposed method allows to assess the accuracy achieved for any given number of considered plane waves.

ABSTRACT. Planar Inverted-F antennas (PIFAs), due to their planar topology and compact dimensions combined with multi-band working frequencies, are becoming increasingly popular in the scientific community and the technology industry places so much emphasis on them. The design and the fabrication of PIFAs on innovative substrates become crucial to facilitate their integration in wireless sensor network systems and to enhance the connectivity of Internet of Healthcare Things (IoHT) network nodes. In this work we propose the fabrication and characterization of a compact (13x26 mm2) PIFA placed on a flexible 250 μm-thick Polyethylene Naphthalate (PEN) substrate working in both the sub-6GHz and 6GHz bands of 5G spectrum. The antenna has been realized by means of a multi-material 3D printer, NanoDimension’s Dragonfly LTM. The use of the 3D printer entails the rapid prototyping and increases the scalability of the process.

ABSTRACT. The exceptional properties of film bulk acoustic resonators (FBARs) such as low power consumption, high quality factors and high working frequencies make them the gold standard for radio frequency resonators. Once in the acoustic domain, the travelling waves frequencies become susceptible to the conditions of the propagating medium. In this context, their fabrication on flexible and wearable substrates represents a strategical step forward to obtain a new generation of highly sensitive sensors. In this work, we propose the fabrication and the characterization of an Aluminium Nitride-based FBAR directly fabricated on a flexible polymeric substrate. The fabrication process results very effective as the resonator shows a clear resonance around 1.56 GHz, a 3dB quality factor of 157 and can be integrated with antennas to accomplish a wireless sensor node.

ABSTRACT. The insertion of a metamaterial (MTM) lens based on Closed Loop Resonator (CLR) into a needle microwave applicator is investigated for a more efficient hyperthermia cancer therapy. Several geometries are designed and optimized, Closed Circular-Ring Resonator (CCRR) with circular loops and Closed Square-Ring Resonator (CSRR) with square loops, with one or more concentric loops. The MTM lens is bended around to the radiating section of the antenna to form a cylindrical 3D structure. Preliminary investigations have been focused to increase the device feasibility and patient wellness. The applicator is a slot coaxial antenna inserted into a surgical needle of 16 G and operating around at the center of Industrial, Scientific, and Medical (ISM) frequency band. The experimental results pertaining to a preliminary fabricated prototype of needle applicator are encouraging, and the simulation results suggest that they could be improved by using the investigated MTM lens.

ABSTRACT. An experimental setup with a solid-state microwave generator and experimental probes has been used to generate controlled ablation patterns on ex-vivo tissues. Correlation of obtained ablation patterns with microwave delivery parameters and probe types has been investigated and characterized.

ABSTRACT. An electromagnetic shielding, operating at f = 2.45 GHz, is designed in the context of food pasteurization treatment. The industrial belt of the plant implies an undesired leakage aperture of the microwave heating chamber, fed by multiple magnetrons to raise the temperature. The shielding consists of a one-wall uniformly corrugated rectangular waveguide followed by an array of graphite rings acting as absorbers of the residual electromagnetic power. The design is performed via a 3D electromagnetic simulation. The proposed electromagnetic shielding succeeds in attenuating the electromagnetic emission, crucial for worker safety and for equipment susceptible to electromagnetic radiation. Moreover, the electromagnetic power reflected by the shielding allows to reduce energy consumption.

ABSTRACT. This paper outlines the development of a continuous microwave-assisted pilot plant for almond disinfestation. A coupled thermal and electromagnetic model was defined in order to predict the temperature profile inside the treatment chamber. Then, a microwave apparatus having five generators suitably placed along the treatment chamber was numerically investigated. Therefore, to test the efficacy of microwaves in pest control of stored almonds, a pilot plant was developed and preliminary tested under variable operating conditions.

ABSTRACT. We present the realization of the Regional Cadaster of radiofrequency electromagnetic field (RF-EMF) sources of Basilicata Region (CA.CEM.Bas.). CA.CEM.Bas. is a georeferenced database, which contains a structured set of technical, logistical and administrative information regarding the RF and low-frequency sources installed in Basilicata territory and can be easily consulted and updated via the web. The Regional Cadaster was developed in compliance with a decree of the Italian Ministry of the Environment and the protection of territory and sea, which set up the National Electromagnetic Cadaster. CA.CEM.Bas. represents a crucial tool supporting the public entities in the activities devoted to the monitoring, prevention and safety related to environmental exposure to EMF.

ABSTRACT. The present study aimed to determine whether autophagy contributes to radiofrequency-induced adaptive response. To this purpose, SH-SY5Y human neuroblastoma cells were exposed for 20 hours to 1950 MHz, UMTS signal, and then treated with menadione, a DNA damage inducer. The results obtained indicated a reduction of menadione-induced DNA damage in samples that were pre-exposed to radiofrequency field, as assessed by the comet assay. Such a reduction was negated when autophagy was inhibited by Bafilomycin A1 and E64d. Moreover, CRISPR SHSY-5Y cell lines defective for ATG7 or ATG5 genes also did not show adaptive response. These findings suggest the involvement of autophagy in the radiofrequency-induced adaptive response, although further investigation is required to extend such observation at molecular level.