Novel Capacitive Pressure Sensor

A new microelectromechanical-systems capacitive pressure sensor with extremely high sensitivity (2.24 ¿F/kPa) is introduced. The sensor essentially consists of a small drop of mercury and a flat aluminum electrode that are separated by a 1 ¿m-thick layer of Barium Strontium Titanate (a high dielectric-constant ceramic). The assembly constitutes a parallel-plate capacitor where the surface area of the electrodes is variable to a high degree. The mercury drop is pressured by a small corrugated metal diaphragm. As the electrode area of the parallel-plate capacitor varies, a total change in capacitance of more than 6 ¿F is obtained.