A 23–35 GHz MEMS tunable all-silicon cavity filter with stability characterization up to 140 million cycles

A connectorized RF MEMS tunable two-pole band-pass filter is demonstrated as the first all-silicon evanescent mode cavity filter operating in the K-Ka band. All filter components are fabricated with cost-effective silicon micromachining techniques. The filter's poles are controlled by two micro-corrugated MEMS diaphragms that are engineered to be independently controlled with voltages below 140 V. Advanced fabrication techniques are applied for the first time to ensure independent pole-frequency control with no additional filter loss and improved fabrication accuracy and stability. The filter's measured tuning range is from 23 GHz to 35 GHz (0–140 V) with fractional bandwidth ranging from 0.8% to 4%. The filter's measured loss varies from 4.2 to 1.5 dB including its connectors. The extracted filter quality factor varies from 530 to 750. The maximum actuation voltage of 140 V is 2× lower than previous demonstrations for similar tuning ranges. The filter's stability has been tested up to 140 million cycles (0–70 V cycling) with no failures observed. The filter exhibits a burn-in period of about 40 million cycles. The filter provides a stable behavior after the initial burn-in period.