Avoiding RF Isolators - Reflectionless Filtering Components for Emerging Wireless Systems

RF isolators are usually employed in RF front-end 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 the 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 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 considerabe 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 problems of RF power reflections in RF front-end chains and classic solutions to circumvent them with their limitations, the main strategies for the design of reflectionless RF passive components as new paradigm will be 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.