UTD-based formulation for the diffraction at the edge of a truncated dielectric screens: surface wave phenomenology

Uniform high-frequency (UTD-based) closed form expressions are given for the case of a truncated dielectric panel, with the inclusion of the surface wave (SW)-space wave diffraction phenomena. In particular, the solution is explicitly developed for the case of an incident plane wave and observation at a finite distance. The field is represented as the sum of the geometrical optics (GO) field, a space wave diffracted field, and a contribution associated with the surface wave-space wave diffraction mechanism at the discontinuity. The surface wave-space wave diffraction contribution is described by uniform high frequency expressions, including the SW propagation and its subsequent diffraction at the edge. The presence of Fresnel functions in both the space wave and SW-induced diffracted fields rigorously provides the continuity across the relevant shadow boundaries (SB). The heuristic extension is obtained by properly introducing the SW poles of the relevant infinite dielectric screens into the simplified 2D spectra. Finally, this heuristically modified 2D solution is introduced into the rigorous 2D-3D transformation machinery. Thus, it is found that the final 3D expressions satisfy the boundary conditions at the dominant asymptotic order.