RF isolators are usually employed in RF front-ends chains to prevent active stages to be damaged by the presence of RF signal-power reflections created by the passive stages (e.g., RF bandpass filters) in their stopband regions. Indeed, such RF signal-power reflections may induce RF amplifiers to operate in non-linear regime or to create additional undesired mixing products in frequency-conversion stages. Whereas passive and active RF isolators avoid this problem, this is done at the expense of higher size/volume and increased DC power consumption, respectively, and higher cost. A more-efficient solution that is recently gaining a considerable research attention may be the exploitation of “reflectionless” RF passive devices, where the out-of-band signal energy is dissipated inside the circuit instead of being reflected back to the source so that RF isolators are no longer needed. The purpose of this webinar is to familiarize the audience with the emerging topic of reflectionless/absorptive RF passive components, which may result in considerably benefits for emerging RF front-end chains of new wireless systems (e.g., 5G and beyond) in terms of energy-efficiency/DC-power-saving, overall size/volume, and cost. After introducing the problematic of RF power reflections in RF front-end chains and classic solutions to circumvent them with their limitations, main strategies for the design of reflectionless RF passive components as new paradigm are described. This includes both mono-functional and multi-functional RF devices in which several RF-analog-signal-processing actions are co-integrated together. Experimental results of several proof-of-concept demonstrators in a variety of technologies will be also presented.
Roberto Gómez-García is a Full Professor with the Department of Signal Theory and Communications, University of Alcalá, Alcalá de Henares, Spain. His current research interests include the design of fixed/tunable high-frequency filters and multiplexers in planar, hybrid, and monolithic microwave-integrated circuit technologies, multifunction circuits and systems, and software-defined radio and radar architectures for telecommunications, remote sensing, and biomedical applications. In these topics, he has authored/co-authored about 125 papers in international journals and 160 papers in international conferences. He was a recipient of the 2016 IEEE Microwave Theory and Techniques Society (MTT-S) Outstanding Young Engineer Award. He is an IEEE CAS-S Distinguished Lecturer (2020-2022). Besides, he is the Editor-in-Chief of IEEE Microwave and Wireless Components Letters (2022-2024) he has served and currently serve as Associate/Guest/Senior Editor for several IEEE, IET, and EuMA journals. He is also a member of the IEEE MTT-S Filters (MTT-5), the IEEE MTT-S RF MEMS and Microwave Acoustics (MTT-6), the IEEE MTT-S Wireless Communications (MTT-23), the IEEE MTT-S Biological Effects and Medical Applications of RF and Microwave (MTT-28), and the IEEE CAS-S Analog Signal Processing Technical Committees.