SAW reflection and bulk-wave loss characteristics of a groove reflector grating

The reflection and bulk-wave loss characteristics of a SAW reflector grating comprised of shallow grooves are treated using the coupled-mode approach well known in the area of optical gratings. This approach offers the following distinct advantages over the previously reported equivalent network approach: (i) it derives the grating characteristics directly in terms of the material constants of the substrate; (ii) it provides quantitative information on the power loss resulting from bulk-wave radiation; and (iii) it can accommodate changes in groove profile or height among the individual grating elements, making this approach amenable for use in the design of tapered arrays. Computed reflection and bulk-wave loss characteristics of a grating comprised of a varying number of identical trapezoidal grooves are presented.