Higher‐order finite‐element analysis of topographic guides supporting elastic surface waves

A method of computing the eigenmodes of acoustic waveguides of arbitrary cross section is described. It is a finite‐element technique, based on a variational formulation of the guided‐wave problem. The accuracy of the method is assessed by comparing numerical and experimental results for a few specific structures. In particular we describe an acoustic surface ridge waveguide with low dispersion over a broad band.