GUIDED-WAVES IN LAYERED CUBIC MEDIA - CONVERGENCE STUDY OF A POLYNOMIAL EXPANSION APPROACH

A new numerical method to compute propagation constants and mode funct ions of a planar layered acoustic waveguide is described. The basic fe ature is the expansion of velocity and stress fields in each layer on different Legendre polynomial bases, which ensures an exponential conv ergence rate of the method. No transcendental equation has to be solve d and also modes that have very close propagation constants (e.g., cou pled Rayleigh waves) an computed with great accuracy. Convergence of t he method is studied and a way to estimate and control the error on th e solutions is discussed. (C) 1998 Acoustical Society of America. [S00 01-4966(98)03710-2].