Interior Green's function solution for a thick and finite dielectric slab

An interior Green's function solution is presented for a two-dimensional thick and finite dielectric slab. In the present development, the source and the field points are assumed to be inside the dielectric slab. The result is composed of two parts. The first part which has a discrete spectrum of eigenfunctions includes the surface wave multiple interactions, and is obtained by using the generalized scattering matrix and method of moments. The second part, which is a closed-form integral, is obtained for a separable dielectric slab that is closely related to the finite slab. The closed form integral is evaluated numerically and added to the surface wave solution. The solution accounts for the mode conversions at the end caps which occur when surface waves are reflected and diffracted. Test cases show very good agreement with a finite-element solver, even when the source is near the end caps.