Catalog of acoustic equivalent networks for planar interfaces

Rigorous equivalent networks are presented in catalog form for a large variety of planar acoustic interfaces between two media. Although these networks are phrased in electrical terms, involving voltage and current and lumped electrical elements, there is nothing electrical in them. The circuits are purely acoustic in content but electrical in form. These networks are consistent with the microwave network approach described in the companion paper [1], which views an overall structure in terms of uniform regions characterized by modal transmission lines and junction regions represented by lumped equivalent networks. The class of junction regions treated here, namely, planar interfaces between different isotropic media, is a very important one since such interfaces occur as basic constituents in many complicated structures which arise in applications as diverse as ultrasonic surface waves and seismology. In acoustics, a fairly involved coupling of waves can occur at these interfaces; in electromagnetics, by contrast, only simple effects arise and the description becomes trivial.