Temperature measurement using surface skimming bulk waves

Acoustic temperature sensors have the advantages of high-resolution, frequency output, and ease of integration with other acoustic sensors but require hermetic packaging to prevent sensor contamination. This slows sensor response time and increases cost. Surface skimming bulk wave (SSBW) devices have been found to be much less sensitive to surface contamination than other acoustic devices however they have not been studied as temperature sensors. The objectives of this work were to study the contamination sensitivity of a 124 MHz quartz SSBW device as a temperature sensor, as well as calibration methods. The SSBW device had over an order of magnitude less sensitivity to mass loading than a similar SAW device. The temperature coefficient of frequency (TCF) was 32 PPM/°C with a deviation from a second order curve fit of ±0.22°C over a 78°C temperature range.