Trapping and Temperature Compensation of Leaky Surface Waves on Lithium Niobate and Lithium Tantalate Using Shallow Gratings

Abstract

A theory of trapping and temperature compensating leaky surface waves with a shallow surface grating has been developed. It was shown at the 1984 Ultrasonics Symposium that a shallow grating could be used to temperature compensate surface transverse wave (STW) propagation normal to the X-axis on rotated Y-cut quartz. Unlike this STW theory, which was limited to horizontally-pol arized shear s urface waves, the present theory has no limitation on the particle displacement polarization and can be used to describe the effect of a surface grating on an arbitrarily-pola rized s urface wave. For this study leaky wave propagation a long the X-axis of rotated Y-cut lithium niobate and lithium tantalate half spaces will be c onsidered. Because of this theory’s increased complexity, an a nalytical solution could not be found and computerized numerical methods must be used to calculate the grating height needed to trap the leaky wave. Once the g rating height needed to trap the s urface wave has been found, we can then calculate the a dditional g rating height needed to achieve temperature compensation using techniques developed in the earlier STW theory.