Calculation of the high-frequency diffraction by two nearby edges illuminated at grazing incidence

The uniform geometrical theory of diffraction (UTD) together with a generalized spectral extension arc applied to calculate the high-frequency scattering by two nearby edges illuminated at grazing incidence. Several examples arc considered which involve the diffraction by a pair of parallel edges where one edge is illuminated by the shadow boundary field of the other. Expressions for the diffracted field have been obtained for plane, cylindrical, and spherical wave illumination with either the electric or magnetic field perpendicular to the edges. Extensive numerical results are given for a pair of staggered parallel half-planes, a thick screen, and a rectangular cylinder. Comparisons with the results calculated by other techniques are also presented to demonstrate the accuracy of the method.