Virtual rays for diffraction coefficients of a composite wedge

This paper presents a new concept of virtual rays has been suggested for constructing diffraction coefficients of a composite wedge. Basically, the suggested method plays an important role in obtaining diffraction coefficients of some penetrable wedges in closed form. The uniform currents induced on the wedge interfaces were derived from the GO field. The complete PO solution could be obtained analytically by applying the uniform currents into the dual integral equations. The error of the obtained PO solution was interpreted by nonzeroness of the artificial field emanating from the uniform currents in the complementary regions, in which the media inside and outside dielectric wedge are exchanged with each other. The concept of complementary regions may be considered as an extension of the null-field method or the extended boundary conditions.