A Quasi-LTI Frequency-Selective SAW Circulator

Abstract

A novel topology to obtain 3 port nonreciprocal propagation in a magnetless medium is here presented. A modulation frequency of 15 MHz guarantees 10 dB of nonreciprocal contrast at 870 MHz by modulating a SAW filter with a switched capacitor network. An unprecedented 40dBc first order Inter Modulation Distortion (IMD) is achieved thanks to unique features of RF acoustic filters, obtaining a Linear Periodically Time Variant (LPTV) circuit behaving as a quasi-LTI circuit.