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.