A Weakly Coupled Tuning Fork MEMS Electric Field Sensor With High Resolution and Wide Measurement Range

High-resolution and sensitive MEMS DC electric field sensors offer the possibility for the integration of detection in multiple fields, such as atmospheric electricity, power grids and biomedical sciences. In this work, a mode-localized sensor prototype based on a double-ended tuning fork design (DETF) is presented. The theoretical derivations and lumped model simulations reveal the key performance enhancements regarding the wide measurement range and high resolution of such a coupled resonator structure. A prototype is fabricated using Silicon-On-insulator (SOI) approaches, which is further tested to achieve a sensitivity of 0.016/(kV/m), a resolution of 21.3 V/m, a measurement range of 200kV/m and a bias instability of 0.29 V/m. The metrics are improved compared to the traditional Euler beam designs and the micro-machined counterparts. This shows the capability to meet the demands for electric field sensing in modern atmospheric electricity, power grids and biomedical sciences, with enhanced sensitivity, measurement range and stability.