TM scattering by conducting strips right on the planar interface of a three-layered medium

Combining the Fourier transform with powerful singular integral equation methods, the authors investigate the scattering properties of a variety of two-dimensional, three-layered planar structures loaded by a strip or a couple of coplanar strips right on an interface. The primary excitation is the lowest-order incident TM (to strip axis) surface wave mode or an incident E-polarized plane wave. In the practical case where the entire space is magnetically homogeneous, the kernel of the integral equations is most conveniently decomposed into a singular closed-form term added to an exponentially convergent inverse Fourier integral. An efficient, accurate, and stable numerical code is obtained and used to determine the strip-induced current densities as well as any quantity of practical interest. Plotted results reveal that by a proper choice of certain geometrical parameters the structures may become very efficient radiators, which can be designed to exhibit either very wideband and high directivity or considerable frequency scanning