Analysis of leaky surface acoustic waves on quartz thin plates bonded to similar-material substrate

Abstract

Abstract The propagation and resonance properties of a leaky surface acoustic wave (LSAW) on quartz thin plates bonded to a similar-material substrate are investigated theoretically. The electromechanical coupling factor K 2 on Z-cut quartz (Z–Q) thin plates bonded to an AT-cut 0°X-propagating quartz (AT0°X-Q) support substrate is calculated to be 0.43%, which is approximately three times larger than the maximum value of a single quartz substrate. A positive temperature coefficient of frequency for LSAW can be produced on a quartz thin plate bonded to a quartz substrate with a different cut angle. By the finite element method, the aluminum thin-film thickness dependence of the resonance properties of LSAW on LST-cut quartz (LST-Q) and LST-Q/AT0°X-Q is analyzed. In the simulation with the optimal Al thin-film thickness, the admittance ratio on the LST-Q/AT0°X-Q is found to be larger than that for the single LST-Q.