RF-MEMS based adaptive antenna matching module

Abstract

To preserve the link quality, in fluctuating operating environments, an adaptive antenna matching module is presented that consists of a 5-bit RF-MEMS switched capacitor array, a bipolar 60/30 V MEMS-biasing voltage generator for improved reliability, and an impedance phase detector that provides information on mismatch. It uses an iterative up-down counting algorithm for robust control. Measurements show proper correction of the antenna reactance, even for a VSWR of 10. The switched capacitor array exhibits a large tuning range from 1 to 15 pF and an insertion loss of 0.4 dB. The detector dynamic range equals 35 dB with an accuracy of 8 degrees from 0.8 to 2 GHz. Adaptive matching will make isolators redundant.