Electric field sensor using electrostatic force deflection of a micro-spring supported membrane

Abstract: An electric field sensor is shown which uses a micromachined micro-spring supported membrane as the sensing element. The sensing mechanism involves electrostatic force to deflect the membrane, and an optical position sensor to measure membrane movement. Measurement resolution was 5kV/m for a dc field and 140V/m for a 49Hz ac field. It is shown that a bias voltage applied to the membrane can be used to increase measurement sensitivity. With a 17kV/m dc bias field, a 0.3V/m ac field at 97Hz was detectable. [Copyright &y& Elsevier]