Electric-dipole radiation over a wedge with imperfectly conductive faces: a first-order physical-optics solution

We solve a three-dimensional (3-D) electromagnetic diffraction problem involving an obtuse wedge with penetrable planar faces and an electric dipole which is parallel to the edge of the wedge. The analytical formulation is based on Stratton-Chu (1941) integrals of the electromagnetic field, which is excited by the dipole source on infinitely extending planes that coincide with the faces of the wedge. Fictitious charges are introduced along the edge to account for the discontinuity of the electromagnetic field on the faces across the edge. We evaluate asymptotically the integral expressions for the electric-field intensity far from the edge to obtain uniformly valid formulas. Our first-order physical-optics solution incorporates single reflection from both faces, the lateral wave, the edge-diffracted space wave, the edge-diffracted lateral wave, and transition terms which ensure that the electromagnetic field is finite and continuous at the single-reflection and lateral-wave boundaries. The numerical results establish the validity of this solution through a reciprocity check and comparisons with other analytical solutions.