Highly Integrated and Tunable RF Front Ends for Reconfigurable Multiband Transceivers: A Tutorial

Abstract

Architectural and circuit techniques to integrate the RF front end passive components, namely the SAW filters and duplexers that are traditionally implemented off chip, are presented. Intended for software-defined and cognitive radio platforms, tunable high-Q filters realized by CMOS switches and linear or MOS capacitors allow the integration of highly reconfigurable transceiver front ends that are robust to in-band and out-of-band blockers. Furthermore, duplexer techniques based on electrical balance concepts are introduced to enable highly integrated and programmable radios for full-duplex applications such as 3/4G transceivers. Several case studies are presented that offer highly linear and low-noise transceiver front ends that satisfy the challenging requirements of cellular standards, yet offer considerably lower cost and size compared to the state-of-the-art transceivers available today.