Patent ID: 8143906

Claim:
A system for sensing a pressure condition in a subterranean environment, comprising: a signal generator, configured and arranged to generate an electromagnetic signal; a sensor probe, locatable in a region of the subterranean environment, the sensor probe including a resonant circuit portion that includes a capacitive element, the resonant circuit portion being configured and arranged to receive energy from the electromagnetic signal and to generate a ringing signal in response to the electromagnetic signal, wherein the capacitive element of the sensor probe is responsive to the pressure condition in the region of the subterranean environment to modulate the ringing signal in accordance therewith; the capacitive element comprising: a first conductor plate having a first conductive layer supported by a first substrate, the first substrate comprising a carbon fiber fabric material; and a second conductor plate having a second conductive layer supported by a second substrate, the first and second conductor plates together defining an adjustable gap therebetween, the adjustable gap being adjustable responsive to the condition to alter a capacitance of the capacitive element; a seal disposed between the first and second conductor plates, the seal constructed and arranged to retain a compressible material in an adjustable gap between the first and second conductor plates and wherein, the adjustable gap is adjustable responsive to the pressure condition to alter the capacitance of the capacitive element and wherein the first and second conductor plates are arranged and comprise materials selected such that a change in the adjustable gap due to a change in temperature is less than a change in the adjustable gap due to a change in pressure; a receiver, configured and arranged to receive the modulated ringing signal; and a processor, configured and arranged to process the modulated ringing signal to obtain a measurement of the condition.