Patent ID: 7414415

Claim:
A sensor for capacitively measuring the distance to a stationary or passing object comprising: a sensor assembly having an electrode for capacitively coupling with the object, a shield that surrounds the electrode and is electrically isolated from the electrode by an insulating layer, and a housing that substantially surrounds the electrode and the shield; a first electrically conductive bridge connected to the electrode and connectable to a first conductor of a transmission cable; a second electrically conductive bridge connected to the shield and connectable to a second conductor of the transmission cable; and a third electrically conductive bridge connected to the housing and connectable to a third conductor of the transmission cable; wherein the electrode and the shield are formed entirely from an electrically conductive ceramic material and the insulating layer and the housing are formed entirely from an electrically non-conductive ceramic material such that the sensor assembly is formed entirely from ceramic materials, and in that the electrically conductive and electrically non-conductive ceramic materials are selected to have substantially similar thermal expansion coefficients, such that the sensor assembly remains virtually stress free at high operating temperatures.