Scattering of s-polarized electromagnetic waves by a 2d obstacle near an interface

Abstract

We consider the scattering of s-polarized electromagnetic waves by a cylindrical scatterer lying in the vicinity of a surface separating two homogeneous dielectric media. The scatterer is a bounded zone of arbitrary shape described by its dielectric constant ϵ( x, z). The upper and lower media are assumed to be homogeneous, isotropic, linear and to have a complex and local dielectric constant. In this communication, an integral equation is used to find the electric field in the inhomogeneous zone. From the knowledge of the field within the scatterer, asymptotic expansions give the far field. Thus, it is possible to compute the diffraction pattern and the scattering cross-section of the scatterer. The numerical results are checked by using the classical criteria of the conservation of energy (optical theorem) and reciprocity. For instance, the relative difference between the scattered flux and the decrease of the flux in the specular direction is currently less than 10 -5; in addition, the reciprocity relations are always verified up to 4 figures of accuracy.