The need for a corner diffraction coefficient in a UTD scheme arises when the leading edge diffracted field experiences a discontinuity as it occurs when the diffraction point disappears from an edge or changes abruptly its location from one edge to the other. The solution proposed will be used to weigh the plane wave spectrum located at a finite distance from the vertex. Also obtained is the asymptotic evaluation of the spectral integrals and for simplicity, the scalar case is treated in this paper and the formulation for hard boundary conditions given explicitly.

Two leading high frequency theories have provided very effective tools for engineering purposes namely the geometrical theory of diffraction (GTD) especially in its uniform extension (UTD) and the physical theory of diffraction (PTD). An incremental theory of diffraction has been developed which provides a unified framework for describing high frequency phenomena. The electromagnetic scattering from planar structures is investigated in order to demonstrate the validity of the incremental theory of diffraction (ITD).

A high-frequency description of the scattering from complex structures that exhibits surface discontinuities such as edges and vertices, is of importance in a wide variety of practical applications. In this paper, a first order, high-frequency solution for the scattering by a corner is presented. The author's formulation is based on the Incremental Theory of Diffraction (ITD), which has been recently developed.