A 19–40 GHz bi-directional MEMS tunable all silicon evanescent-mode cavity filter

Abstract

This paper presents, for the first time, a new tuning technology based on bi-directional MEMS actuators for high-quality all-silicon evanescent mode cavity filters. Such bi-directional tunability provides a feasible solution to restore frequency tunability from degradation caused by aging effects such as creep and stress relaxation. The fabricated proof-of-concept filter demonstrates a measured tuning range from 18.9 to 39.6 GHz, in which the forward (main) actuation tunes from 21.3 to 39.6 GHz with 120 V and the reverse (corrective) actuation tunes from 21.3 down to 18.9 GHz with 2 V. The measured filter insertion loss varies from 3.14 to 0.78 dB and its instantaneous bandwidth from 0.31 to 1.81 GHz. The unloaded quality factor is extracted as 265-510 which is comparable to the state-of-the-art filter of this type employing conventional uni-directional tuners.