A High-Performance Mode-Localized Accelerometer Employing a Quasi-Rigid Coupler

Abstract

An ultra-sensitive mode-localized accelerometer is reported in this letter. In order to lower the coupling factor of the coupled resonators thus improving the parametric amplitude ratio sensitivity, a stiff anchor support is employed as a mechanical coupler between resonators. A coupling factor of $7.4\times 10^{-5}$ was obtained, which is so far the lowest mechanical coupling factor that has been reported for weakly coupled MEMS sensors. As a result, the proposed mode-localized accelerometer demonstrates an input-referred bias instability as high as 280ng within an integration time from 3s to 300s, and an input-referred noise floor of 250ng/ $\surd $ Hz, without utilizing temperature control or other environmental compensation, benchmarking as the highest resolution mode-localized accelerometer to-date. These metrics are comparable to state-of-the-art MEMS frequency-modulated resonant and capacitive accelerometers while exhibiting superior common-mode rejection to environmental effects.