Mechanically Modulated Microwave Circulator

TL;DR

This paper introduces the first MEMS-only microwave circulator using a differential FBAR design that employs mechanical modulation via bending modes, achieving high isolation and low insertion loss at GHz frequencies.

Contribution

It presents a novel MEMS-only circulator design utilizing differential FBARs with mechanical modulation, eliminating the need for varactors or switches.

Findings

Achieves 61.5 dB isolation at 2.68 GHz

Insertion loss of 1.8 dB

Isolation bandwidth of 4.7 MHz at -25 dB

Abstract

This work presents a differential FBAR circulator that uses the bending mode to mechanically modulate the FBAR mode without any varactors or switches. The differential FBAR circulator achieves a 61.5 dB isolation (IX) with an insertion loss (IL) of 1.8 dB at 2.68 GHz, demonstrating the first MEMS-only circulator. The isolation bandwidth at -25 dB is 4.7 MHz and power handling of the circulator is limited by the FBARs to +34 dBm.