A micro-aperture electrostatic field mill based on MEMS technology

A miniature electrostatic field mill has been constructed using a silicon surface micromachining MEMS fabrication process. A moving shuttle with a viewing aperture of 10 μm2 periodically exposes and covers a charge sensing electrode, thus allowing the latter to measure electrostatic field magnitudes. A signal output on the order of 40 nV per V/m of measured field is reported. Electrostatic force is produced by interdigitated comb drives. Mechanical restoring force is produced by a folded beam suspension system. Techniques for reducing unwanted coupling of drive signals are discussed.