A 20–40 GHz tunable MEMS bandpass filter with enhanced stability by gold-vanadium micro-corrugated diaphragms

摘要

This paper reports the first octave-tunable K-band MEMS continuously tunable band-pass cavity filter with enhanced frequency stability by incorporating a creep-resistive Au-V (2.2 at. % V) micro-corrugated diaphragm (MCD) tuner. All filter components are fabricated with silicon micromachining techniques. The filter's measured tuning range is from 20 to 40 GHz with fractional bandwidth ranging from 1.9% to 4.7%. The filter's measured loss varies from 3.09 to 1.07 dB including its connectors. The Au-V tuner results in significantly improved frequency stability with a 7× slower drift rate (phase II creep) compared to previously reported stare-of-art MEMS tunable filters based on Au-based MCD tuners. However, this comes at a cost of an additional 0.15-0.9 dB loss due to the higher resistivity of AuV. This large increase in frequency stability with a low-to-moderate increase in loss is a desirable trade-off for most applications.