A wireless pressure sensor based on surface transverse wave

Abstract

The surface acoustic wave (SAW) pressure sensor is usually composed of a clamped circular quartz membrane, where a one-port Rayleigh wave mode resonator is fabricated. In order to improve the reliability and the accuracy of the wireless pressure sensor, a wireless pressure sensor based on surface transverse wave (STW) is studied. Combined with the perturbation theory proposed by Tiersten and the Green's function simulator, the pressure-induced frequency shifts for STW on quartz are calculated. The calculated results demonstrate that the cut orientation in vicinity of BT cut membrane has simultaneously both high pressure sensitivity and delay temperature stability of STW. The pressure sensitivity is over three times that of the ST-cut quartz for SAW. In order to further improve the sensitivity of the sensor, a novel cantilever package is proposed. The geometry of the sensor is determined by using FEM software. The experimental data show that the pressure sensitivity is sufficiently high and the relative frequency shift varies linearly.