Exact and approximate techniques for scattering from targets embedded in a layered medium.

Abstract

To be able to accurately compute scattering from a target embedded in a layered medium (waveguide), the scattering and propagation problems must be solved as a single boundary value problem. This is accomplished by solving the wave equation in an environment that contains both the target and the waveguide and satisfying boundary conditions on the surface of the target and the boundaries of the waveguide. One way that this can be accomplished is by the use of the virtual source technique, which replaces the target with a collection of sources whose amplitudes are determined from the boundary conditions on the surface of the target. This method converts the problem of scattering from a target in a waveguide to a multisource propagation problem. In this paper, the virtual source technique is used to compute scattering from a target in a waveguide and various ways to speed up computation are examined. These include the use of various propagation models to propagate the field produced by the virtual sources to the receiver. Various solutions are compared and the advantages and disadvantages of each model are discussed.