Characteristics of surface acoustic waves propagating obliquely in periodic electrode gratings

The characteristics of surface acoustic waves (SAW) propagating obliquely in electrode gratings are investigated, with the mass-loading effect taken into account. The velocity of the surface waves, as well as the attenuation, piezoelectric coupling and beam-steering are obtained as a function of the propagation angle with respect to the grating axis. The slowness curves for SAW propagating under periodic electrode gratings are compared with slowness curves for the same SAW propagating on free or shorted homogeneous surfaces as well as under a thick homogeneous metallic layer. Examples are presented for the SAW of 42.75/spl deg/YX quartz and the leaky-SAW of 36/spl deg/YX lithium tantalate.