Multiple Parameter Decoupling for Resonant MEMS Sensors Exploiting Blue Sideband Excitation

This work reports a multiple-parameter decoupling (MPD) method based on resonant MEMS sensors subject to blue-sideband excitation (BSE), thus enabling simultaneous separation of the cross-coupled physical quantities, e.g. acceleration and temperature, of a single MEMS sensor. Such a technique exploits the property of the BSE that multiple vibration modes of the resonator can be excited at the same time. The proposed MPD algorithm is applied to two distinct resonant MEMS sensors, i.e. a base-line resonant electrostatic force sensor, and a vacuum-packaged resonant MEMS accelerometer. The target measurand of each type of resonant sensor is enveloped by external temperature changes, but the MPD can successfully decouple the measurand from the temperature changes in a single operation. The cross-sensitivity was suppressed by 31 dB and 35 dB for each device, respectively. The decoupled parameters are consistent with the stand-alone measurements, validating the preliminary functionality of the proposed method. The results confirm the merit of the BSE technique for resonant MEMS sensors, and demonstrate significant potential for in-situ temperature fluctuation suppression in high-precision resonant sensors as well as single-device multiple-parameter monitoring.