Comparison of acoustic wave pressure sensors for TPMS applications

Abstract

We study and compare the pressure sensitivities of different area Rayleigh Lamb wave (RL) mode (S1 mode) and FBAR resonators. The studied RL-mode and FBAR resonators operate at 785MHz and 628MHz respectively. The resonators are fabricated on a released membrane with AlN as the piezoelectric layer. The resonators are hermetically sealed and the manufacturing process uses standard micromachining techniques throughout. The devices exhibit a pressure sensitivity over a range of 15 - 80psi, suitable for Tire Pressure Monitoring Systems (TPMS). The sensitivities of different area resonators are compared.