Three electrodes touch-mode capacitive pressure sensor

A three-electrode capacitive pressure sensor for touch-mode operation with sensitivity of 0.030 pF/kPa (or 10.4 mV/kPa using CP-10 C/V converter circu it) in the pressure range of 170-280 kPa is presented with theoretical expl anation of experimental results. A special ring structure is designed to in tegrate a sensing capacitor and a reference capacitor into the same cavity to partially cancel out the temperature effect. A third electrode is includ ed to eliminate two-level connections without reducing its pressure sensiti vity. The sensor offers the advantages of simple fabrication processes, pla nar connections, as well as high sensitivity, near-linear output, and large over-range pressure.