Electret-based low power resonator for robust pressure sensor

We have developed a membrane-less pressure sensor based on squeeze-film damping in a 2-μm driving/sensing gap of a silicon ring-shaped resonator. Its sensing range is from sub-atmospheric to over 1MPa; very wide-range pressure measurement is possible with one sensor element. An electret film having the 200-V-bias voltage was incorporated to the resonator; this allows the excitation of the resonator at very low AC voltage. This membrane-less pressure sensor has robust and low power consumption (nW-range) characteristics.