SYSTEM AND METHOD FOR MEASURING VARIABLE IMPEDANCE ELEMENTS IN A WIRELESS SENSOR

摘要

A wireless remote sensor (110) that is powered by an inductive transmitter (112) and is configured to produce an oscillating wave that varies based on one or more sensed parameters. The oscillating wave is communicated to the inductive transmitter (112) by reflected impedance, where it can be detected to determine the sensed value(s). In another aspect, the present invention provides a wireless remote sensor with a Wheatstone bridge arrangement having an internal resonant circuit to produce an electromagnetic field indicative of the sensed value. In a third aspect, the present invention provides a wireless remote sensor with optical feedback from a reference circuit and a sensor circuit. In a fourth aspect, the present invention provides a wireless remote temperature sensor having coils printed on a material with a high coefficient of thermal expansion so that the size and/or shape of the coils varies as the temperature increases or decreases.

主权项

1. A wireless remote sensor for sensing a parameter comprising:
a receiver coil configured to wireless receive power from a wireless power transmitter; and an oscillating circuit coupled to said receiver coil whereby oscillations of said oscillating circuit are communicated to the wireless power transmitter by reflected impedance, said oscillating circuit having a variable impedance element that varies with a value of the parameter to be sensed, wherein a duty cycle of said oscillations varies based on variations in said variable impedance element.