Patent ID: 6014029
Filing Date: 2000-01-11
Classification: G01N,G01R,Y10T

Abstract:
A device for sensing changes in the permittivity of a sample of a medium exposed to an environment having one or more elements, the device comprising:an LC oscillator circuit having an inductance element and a capacitance element, the inductance element having a relatively constant value, L, and the capacitance element having a variable value, C, wherein the value of the capacitance element is dependent upon the permittivity of the sample in which the capacitance element is disposed, the LC oscillator circuit having a resonance frequency dependent upon the value of the inductance element and the value of the capacitance element given by the relationship 1/(2.pi.(LC).sup.1/2), wherein the capacitance element includes first and second conductive elements substantially surrounded by an insulating dielectric material so that the first and second conductive elements are substantially prevented from being exposed to one or more elements of the environment of the sample and so that the first and second conductive elements are prevented from contacting one another, the inductance element having a first lead and a second lead, the first conductive element being electrically coupled to the first lead of the inductance element and the second conductive element being electrically coupled to the second lead of the inductance element; and,an output circuit coupled to the LC oscillator circuit adapted to output a signal representative of the permittivity of the sample based upon the resonance frequency of the LC oscillator circuit, wherein changes in the output signal are indicative of changes in the permittivity of the sample.