Internal phase inversion narrow bandwidth MEMS filter

This paper reports a novel capacitively coupled twin beam resonator internal phase inversion filter fabricated in a SOI MEMS process. A narrow bandwidth of 0.0157% is demonstrated with a low control-voltage of -0.87 V. The bandwidth can be substantially reduced by utilizing an electrical coupling spring as opposed to a mechanical coupling-spring. The bandwidth is tunable with control achieved using a differential DC bias. A summary and comparison with other members of the phase inversion filter family is also included.