A 600 kHz electrically-coupled MEMS bandpass filter

This paper presents a 600 kHz MEMS bandpass filter implemented using electrical coupling of single crystal silicon HARPSS micromechanical resonators. Passive and active filter synthesis approaches based on electrical coupling of capacitive MEMS resonators are introduced and discussed. A third order passive bandpass filter at the center frequency of 600 kHz with a bandwidth of 125 Hz, a stopband rejection of 48 dB, and a 20 dB-shape-factor of 2.1 is demonstrated. A quality factor (Q) enhancement technique based on active electrical cascading of the resonators is also presented. A 3-stage active cascade at 600 kHz demonstrated a 2/spl times/ increase in the effective Q.