A Resonant Electrostatic Field Microsensor With Self-Compensation for Sensitivity Drift

Electrostatic field microsensors (EFMs) are widely used in many fields, and the environmental adaptability is one of the major concerns for EFMs development. This article proposes a resonant EFM with self-compensation for sensitivity drift, which is suitable for outdoor applications. The proposed EFM-sensitive structure mainly consists of sensing electrodes and reference electrodes, where the sensing electrodes are designed to measure the electrostatic field, and the reference electrodes are used to detect the vibration amplitude and phase of the movable structure. With the reference electrodes output, the EFM can track the resonant frequency by phase-locked loop (PLL) circuit automatically and correct the sensing output signal in real time. Experimental results demonstrated that the proposed EFM reached a linearity of 0.21% and a total uncertainty of three round trips within 1.34% in the electrostatic field range of ±18 kV/m and achieved a sensitivity drift within 3.0% in the temperature range of −40 °C to 70 °C, which means that it realized a good self-compensation performance.