Q-factor Tuning and Closed-loop Control for a Resonant Electric Field Micro-Sensor

A method that utilizes vibration velocity signal and differential combs to improve the equivalent Q factor of MEFS is proposed in this study to address charge accumulation on the metal cap surface of an MEMS-based electric field sensor (MEFS) with vacuum package. The MEFS system is characterized by a high degree of nonlinearity, so the averaging method is used to analyze system stability and vibration amplitude. Theoretical and simulation results show that the proposed method is feasible. Experiment results indicate that the larger is the referenced voltage, the larger is the zoom stable vibration amplitude, and the shorter is the transient time. The resulting signal-to-noise ratio is about 92 dB, and the vibration amplitude shows a deviation of 0.2% in 6 min.