A Solution for the Plane Wave Diffraction by the Discontinuity Between Two Co-Planar Metamaterial Sheets

A high-frequency approach is described to investigate the scattering by a junction between double negative metamaterial (DNG MTM) sheets. These last are lit by an incident plane wave and have same thickness, but different electric and magnetic parameters, thus assuring discontinuities of reflected and transmitted fields across the junction. The proposed methodology permits to evaluate the diffraction contribution as the sum of two independent terms arising from the scattering process including electric and magnetic equivalent sources under the physical optics (PO) approximation. The formulation of this wave contribution permits its use in the enclosure of the uniform geometrical theory of diffraction (UTD). Useful approximations and integral representations are adopted together with asymptotic evaluations to obtain the diffraction matrix elements. Accordingly, these last account for convenient reference systems, the approximated equivalent currents, and the typical function of the UTD. A full-wave numerical tool is exploited to assess the correctness of the proposed formulation.