Modeling and implementation of an innovative micro proximity sensor using micromachining technology

The modeling and implementation of an innovative micro capacitive proximity sensor using micromachining technology are described. The proximity sensor works on the principle of fringing capacitance. The target object to be measured does not need to be part of the measuring system and can be either a conductor or a nonconductor. By selecting a set of geometrical parameters, this sensor is capable of precise measurement of proximity in the range from micrometers to millimeters. The capacitance change is quite significant for such small sensing structures, though it is only a fraction of a picofarad. The micro size of the sensor makes it possible to mount it in many space-constrained places.