Excitation and scattering of electroelastic surface waves via an integral equation approach

Abstract

The determination of the surface charge distribution on the fingers of an interdigital transducer is the single most important step in the analysis of such transducers. Similarly, the determination of the stress distribution at the interface of a plane surface and a topographical irregularity is the single most important step in computing the scattering of a surface wave by such an irregularity. In this paper we apply the Fourier transform to derive an integral equation for the surface charge distribution on a finite interdigital transducer. The Fourier integral equation is inverted by utilizing an expansion of the surface charge in piecewise polynomials and then employing the method of moments (or Galerkin's method) to reduce the integral equation to a matrix equation which is then solved on the computer. The evaluation of the matrix elements is accomplished by a combination of analytical (contour integration) and numerical techniques. A similar approach is made to solve the problem of scattering of a surface wave from a topographical irregularity.