A UNIFORM RAY APPROXIMATION OF THE SCATTERING BY POLYHEDRAL STRUCTURES INCLUDING HIGHER-ORDER TERMS

A uniform ray representation of the far field scattered by flat plate structures is investigated by postulating an approximation of the surface current on each face of the object, which is subsequently integrated either in closed form or asymptotically in terms of the well-tabulated edge transition function. Specifically, the current on each plate is approximated, in addition to the usual physical optics (PO) component, by a primary nonuniform current, obtained from the canonical solution to the wedge problem and truncated at edges of the plate, as well as a secondary nonuniform current induced by doubly diffracted fields and expressed in terms of an equivalent edge source. The superimposed effect ef the rays resulting from the primary and secondary nonuniform current integration improves the agreement of the calculated pattern as compared with method of moments (MM) computations.