Measuring atmospheric electric field using novel micromachined sensor

A new type of micromachined electrostatic field sensor (EFS) that can be used to measure atmospheric field has been demonstrated in this paper. The sensor structure is designed to work at resonant frequency for maximum sensitivity to electric fields. SOI (Silicon on Insulator) micromachining technology was used to fabricate the sensor. The sensing area of this sensor is only 5mm×5mm and it requires only less than 1μW to drive its shutter. The device gives high quality factor (Q) of approximately 31034 at a vacuum degree of ~1mTorr with lower actuation voltages (i.e., 250mV DC and 20mVp-p). Tested in ambient air conditions, a minimum detectable DC electric field with current sensor designs better than 50V/m is also achieved. The use of a miniature sensor also helps to measure local atmospheric electric field accurately since the field distortion caused by the sensor is minimum.