Energy-trapping mode in lateral-field-excited acoustic wave devices

Abstract

We have analyzed the energy-trapping phenomenon of the thickness-shear vibration in lateral-field-excited (LFE) acoustic wave devices based on elastic wave propagation theory and the cutoff frequency. The standard LFE device does not support the energy-trapping effect, which is significantly different from thickness-field-excited devices. However, energy trapping in LFE devices can be achieved by placing an additional mass-loading layer in the gap region between the two working electrodes. A 5 MHz energy-trapping LFE device is fabricated and tested. The experimental results are in close agreement with the theoretical analysis.