Comparison Of Acoustic Wave Pressure Sensors For Tpms Applications

We study and compare the pressure sensitivities of different area Rayleigh Lamb wave (RL) mode (S-1 mode) and FBAR resonators. The studied RL-mode and FBAR resonators operate at 7 8 5MHz 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.