Diffraction at a thick screen including corrugations on the top face

A closed-form high-frequency solution is presented for the near-field scattering by a thick screen illuminated by a line source at a finite distance. This solution is applicable to a thick screen with perfectly conducting side walls and either perfectly conducting or artificially soft boundary conditions on the face joining the two wedges. This latter condition is obtained in practice by etching on that face quarter of a wavelength deep corrugations with a small periodicity with respect to the wavelength. It is shown that the artificially soft surface provides a strong shadowing for both polarizations; thus, it is suggested that such configurations may usefully be employed to obtain an effective shielding from undesired interferences. Several numerical calculations have been carried out and compared with those from a method of moments (MoM) solution for testing the accuracy of our formulation, as well as to demonstrate the effectiveness of the corrugations in shielding arbitrarily polarized incident field.