Analysis of high velocity pseudo-surface acoustic waves (HVPSAW) in quartz periodic structures with electrode fingers

Abstract

A finite element study of the piezoelectric Lagrangean equations for frequency-temperature behavior was performed for a two-dimensional periodic high velocity pseudo surface acoustic wave (HVPSAW) structure of quartz. Plane strain assumptions were used to enable a two-dimensional analysis of straight crested HVPSAW in the structure. The HVPSAW modes found on a partially metallized substrate surface has a symmetric electric potential field, therefore, the modes can be driven by the usual IDT array. The attenuation of the HVPSAW mode is strongly affected by both the electrode height and crystal cut angles. Strong KVPSAW modes with good frequency-temperature behavior can be obtained by a proper combination of electrode material, electrode height and the substrate cut angle. The HVPSAW mode is "leakier" than its PSAW counterpart.