SAW properties of langasite with Euler angles [0°,140°,25°

Abstract

For the past few years there has been considerable interest in using Langasite (LGS) as a substrate material for SAW devices. One interesting orientation of LGS is the one given by the Euler angles [0/spl deg/,140/spl deg/,25/spl deg/]. For accurate design simulations we need experimental values for the different material parameters. In this paper the results from measurements of the key parameters of LGS [0/spl deg/,140/spl deg/,25/spl deg/] are presented. These include the SAW velocity as a function of propagation direction measured by using a laser probe, and measurements of the SAW velocity and propagation loss as a function of frequency. Empirical formulas based on these measurements are established. In addition, the coupling-coefficient, effective permittivity, and temperature coefficients of delay are presented. These measurements confirm previously reported values, except for the coupling coefficient, where the value reported here is somewhat higher than previously reported.