A New Method of Surface Acoustic W ave Pressure Sensing Based on Acoustic Attenuation Mechanism

This work illustrates a new pressure sensing method by measuring the surface acoustic wave (SAW) propagation attenuation. The quality value (Q value) of the sensing chip decreases with the external pressure because of the energy radiation of the Rayleigh wave. This method abandons the traditional pressure-sensing structure, which can expand the measurement range and eliminate the negative effects, such as hysteresis and creep arising from the sealant layer. The sensing chip is developed by the standard photolithographic technique. A high Q value of over 9000 is achieved from the developed sensing chip operating at approximately 430 MHz. Then, the pressure sensing experiment is conducted using the developed sensing chip, which demonstrates excellent performance in the 0.1–4-MPa range, with low hysteresis of −2.02%, excellent nonlinearity of −0.44%, low-temperature drift coefficient of 0.01068 ppm/°C, and the maximum relative error of −2.453%. Excellent stability and consistency in several rounds of experiments are also obtained.