EM PLANE-WAVE DIFFRACTION BY A PLANAR JUNCTION OF 2 THIN MATERIAL HALF-PLANES - OBLIQUE-INCIDENCE

A uniform geometrical theory of diffraction (UTD) solution is developed for analyzing the phenomenon of high-frequency diffraction of an obliquely incident plane wave by a two-part thin, planar transparent material slab. The solution is obtained by appropriately combining two solutions for the two related configurations involving perfectly conducting electric and magnetic ground plane bisections of the original slab. The analysis is based on the Wiener-Hopf technique, and each of the grounded material half-planes is assumed to be electrically thin so that it can be modeled by a generalized impedance boundary condition of 0(t), where t is the corresponding slab thickness. It is shown that to solve the boundary value problem completely, an additional condition related to the field behavior at the junction of the two material half-planes needs to be imposed besides the boundary and radiation conditions as well as the usual edge condition. This junction condition is determined by matching an approximate quasi-static solution, which is developed in the proximity of the discontinuity, with the corresponding external Wiener-Hopf solution in the common region of overlap. The solution thus obtained automatically satisfies reciprocity. It is shown that the new UTD solution obtained here reduces to known results and the numerical results based on it agree very well with a corresponding independent moment method solution.