Patent ID: 7113087
Filing Date: 2006-09-26
Classification: G01V,G06F,Y02D

Abstract:
1. A proximity detection system for sensing the presence of an object or body portion in contact with or close proximity to another object, comprising: a radio frequency (RF) signal source providing RF signals; a transmission pathway connected to the RF source; an antenna connected to the transmission pathway; a directional coupler having a main line in electrical communication with the transmission pathway and a coupled line, the directional coupler producing a signal on the coupled line which varies in response to changes in antenna and transmission line impedance matching caused by presence of an object or body portion; a signal detector in electrical communication with the coupled line and responsive to signals produced in the coupled line by the main line, wherein the signal detector produces an output signal that is within an output range, the output range corresponding to a range of antenna-transmission line impedance mismatch; and a controller in communication with the signal detector, the controller configured to provide, in relation to the output signal, a state signal indicative of the presence or absence of an object or body portion in contact with or close proximity to another object.