Design of a SOI MEMS resonant electric field sensor for power engineering applications

This paper presented a novel resonant electric field sensor (EFS) based on SOI fabrication process for power engineering applications. The sensor architecture has three major blocks: a vibration shutter, sensing electrodes, and a driving electrode that feeds back to the shutter. The EFS structure is designed to work at resonant frequency for maximum sensitivity to electric fields. Prototyped by the SOI fabrication process, the device gives quality factor (Q) of approximately 31034 at a vacuum degree of ~1mTorr with lower actuation voltages (i.e., 250mV DC and 20mVp-p) than other reported electrostatic driven EFS. Tested in ambient air conditions, the device has an improved uncertainty of 1.09% in a measured range of 0-50kV7m DC electric field. A minimum detectable DC electric field with current sensor designs better than 50V/m is also achieved. In addition, the sensor can also be measured AC electric field.