Temperature compensated pressure sensor

This paper presents results from a novel 1 GHz temperature compensated pressure sensor for telemetric transmission of the measured data. The sensor is based on a 1 GHz transmitter using a temperature compensated oscillator stabilized with a surface skimming bulk wave/surface transverse wave (SSBW/STW) combined filter (CMRF). This sensor converts the pressure changes into a shift of the oscillator frequency. The relative frequency shift is about 500 ppm. To eliminate the frequency temperature dependence of the sensor, the oscillator is temperature compensated. The overall temperature instability is ±1.2 ppm in the temperature range of (-30...+60)°C which provides a pressure measurement range of 250/1, where the denominator is the relative temperature induced frequency drift. The absolute accuracy is less then 1% in the temperature range of (-30...+60)°C and the resolution is less then 0.1%. The useful dynamic range is much wider, when fast changing pressure, such as sound pressure, is measured. In this case the dynamic range is limited by the oscillator phase noise