Scattering by Gaps in Coated Structures

Abstract

The electromagnetic scattering from an isolated conductor-backed dielectric gap is studied using a boundary integral approach. To facilitate numerical implementation, the specular solution and the surface wave contribution are removed from the boundary integral equation. Consequently the discretization domain of the infinite structure can be reduced to a localized region near the gap. Numerical diffraction coefficients and surface wave launch coefficients are extracted from the scattered field. The results of this approach are validated against a spectral integral solution to the gap and excellent agreement is observed. Solution to a coated strip with a gap is constructed one mechanism at a time via the high frequency ray framework. This numerical "building block" approach provides a clear physical picture of the complex scattering mechanisms in coated structures.