A Resonant MEMS Accelerometer Utilizing AC Polarization

In this paper, we present a resonant MEMS accelerometer (RXL) using AC polarization voltage as an alternative to the existing DC polarization schemes. By making full use of the intrinsic frequency mixing property of a parallel plate capacitive transducer, we are able to down-convert the oscillation frequency to 10kHz, an order of magnitude lower than the resonator's intrinsic first fundamental mode frequency of 157.5kHz in contrast to the standard approach relying only on a DC polarization voltage. With this approach, a minimum bias stability of 5.9μg has been achieved at an integration time of 0.2s, and the noise floor is 1.7μgHz ^1/2 . Compared to DC polarized configuration, the improvement in bias stability and noise floor is 1.7 times and 2 times respectively.