Spurious acoustic responses in SAW devices

Substantial documentation of the character of spurious responses in SAW devices has shown that they can be completely characterized as families of plate modes when the substrates have parallel top and bottom surfaces. Presented here are theoretical plate mode calculations and the corresponding experimental results for commonly used substrate orientations. It is shown that quantitative terminal response predictions are possible when all the plate modes are included in the analysis. Results for a new substrate cut, 46° (ZYW) LiNbO3, show that it can have lower than -60-dB spurious modes relative to the Rayleigh mode.