Analog Devices, Inc.
Differential z-axis resonant accelerometry

Abstract:

A MEMS resonant accelerometer includes two proof masses configured to resonate when driven with periodic signals. Each proof mass includes a resonator structure that vibrates relative to the proof mass and a dummy structure that does not resonate. When driven by a periodic drive signal, the resonator structures of the two proof masses may be used to determine the magnitude of acceleration in the direction perpendicular to the planes of the proof masses by sensing the frequency at which the resonators vibrate. For example, a differential oscillation frequency may be computed from the two sensed frequencies. The dummy structures are used to make the mass distribution of the two proof masses similar.