Scattering by conductor-backed dielectric gaps

The electromagnetic scattering from two-dimensional conductor-backed dielectric gaps was studied previously, but the isolated contributions from the gap and surface wave phenomena were not extracted. In the present work, two different approaches are implemented to attack the dielectric gap problem and extract the diffracted field and surface wave contributions of the gap. The first approach uses a boundary integral equation formulation. 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 is reduced to a localized region near the gap. The second approach is a spectral integral formulation. This formulation utilizes the Green´s function for the conductor-backed dielectric in a volume integral equation. The results of these two approaches are validated against each other and the surface-wave excitation coefficients at the gap are extracted.<>