Design of a thermally driven resonant miniature electric field sensor with feedback control

A thermally driven resonant miniature electric field sensor (MEFS) with feedback control has been designed. It is mainly comprised of grounded shielding electrodes, bent beam thermal driver, positive and negative sensing electrodes and driving displacement amplitude control unit etc, the shielding electrodes are driven by a cascaded bent beam thermal driver to periodically cover or expose the positive and negative sensing electrodes under them, the driving displacement feedback control unit is used to maintain the displacement amplitude of the shielding electrodes. The thermally driven resonant MEFS has the advantage of small size, light weight, low driving voltage, low drive detection cross talk noise etc. The driving displacement amplitude feedback control unit can dramatically decrease the influence of temperature change on the vibration displacement of the shielding electrodes. When activated with a square wave of plusmn2 V amplitude at a frequency of 20 kHz, the electric field intensity resolution of the thermally driven resonant MEFS without feedback control can reach 101.7 V/m.

I. Introduction

Electric field strength is a very basic and important physical parameter. It is needed to be detected in a lot of fields. For example, in the aviation field, too high electric field strength will trigger lightning to the missile and satellite etc. In the industrial field, too high electric field strength will cause Electrostatic Discharge (ESD) problem to electronic devices.