A Low-Noise MEMS Gravimeter Capable of Attaining Stable Low Resonant Frequency at Various Tilt Angles Through Adjusting Curved Beams’ Width

Abstract

MEMS gravimeters capable of accurately measuring changes in gravitational acceleration play a vital role in various application fields such as geological studies, crustal deformation monitoring, and solid tide observation. Researchers have rendered the MEMS gravimeters more sensitive by lowering their resonant frequency, allowing for detecting the subtle changes in gravitational acceleration. However, these devices achieve low and stable resonant frequencies only when the angle between their sensitive axis and the horizontal plane is 90°. Although the resonant frequency remains low when this angle is less than 90°, it becomes unstable. To address this issue, we propose a novel MEMS gravimeter that can maintain a consistently low and stable resonant frequency by adjusting the width of the curved beam (CB), even when the angle is less than 90°. Simulation results demonstrate that adjusting the CBs’ width from 5 to $20~\mu $ m enables this gravimeter to maintain a stabilized low resonant frequency (<10> $20~\mu $ m exhibits a noise power spectral density of $9.2~\mu $ Gal/ $\surd $ Hz at 6 Hz and a bias instability of $4.1~\mu $ Gal with an integration time of 1800 s.