DIFFRACTION BY AN ARBITRARY-ANGLED DIELECTRIC WEDGE .1. PHYSICAL OPTICS APPROXIMATION

Abstract

A complete form is presented of the physical optics solution to the diffraction by an arbitrary-angled dielectric wedge with any relative dielectric constant in both cases of E- and H-polarized plane wave incidences upon one side of two dielectric interfaces. The solution, which is obtained by performing physical optics approximation to the dual integral equation formulated in the spatial frequency domain, is constructed by the geometrical optics terms, including multiple reflection inside the wedge and the edge diffracted field. The diffraction coefficients of the edge diffracted field are represented in a quite simple form as two finite series of cotangent functions weighted by the Fresnel's reflection coefficients. Far-field patterns of the physical optics solutions for wedge angle 45-degrees, relative dielectric constants 2, 10, and 100, and E-polarized incident angle 150-degrees are plotted in figures, where abrupt discontinuities appear at dielectric interfaces. The error of the physical optics solution is also interpreted explicitly by nonzeroness of the edge diffracted field in the complementary plane where two media inside and outside the dielectric wedge are exchanged with each other.