TE characterization of resistive strip gratings on a dielectric slab using a single edge-mode expansion

Closed-form expressions are derived for the TE scattering by a narrow resistive strip array in the presence of a dielectric slab. This is accomplished by introducing a single edge-mode expansion to represent the strip current density followed by a Galerkin´s solution of the pertinent integral equation. The accuracy of the derived approximate expressions are examined by comparison with a moment method solution and several curves are shown, illustrating how the different array parameters affect the reflectivity and transmissivity of the array. Particular attention is given to the free-standing resistive strip array where an equivalent uniform resistive sheet is constructed for simulating the original periodic structure. The reactance of this equivalent sheet is compared with published expressions pertinent to the metallic strip array