A spectral approach to 3-D object scattering in layered media applied to scattering from submerged spheres

A spectral formulation for 3-D object scattering in a layered medium is described. The formulation is valid when the source and receiver are sufficiently far from the object that multiple scattering between the object and waveguide boundaries can be neglected and the scattered field can be expressed as a linear function of the object’s plane wave scattering function. An analytic expression is then derived for the field scattered from a spherical object in a stratified medium. Since the expression is in terms of 1-D wave number integrals, it is computationally efficient to implement, allows detailed investigation of the scattered field in the vicinity of the object, and enables scattering of evanescent waves to be incorporated by analytic continuation. Computations for a noncompact sphere (1