ASYMPTOTIC EDGE-AND-VERTEX DIFFRACTION THEORY

Uniformly asymptotic formulae for edge-and-vertex diffraction in the t ime-domain, involving elementary functions of time, traveltimes and GT D amplitudes, are derived. Explicit expressions for diffraction at a p yramid and a triangle are constructed. They can be applied to the nume rical calculation of a field reflected and diffracted at 3-D objects w ith sharp edges and to reflection from triangulated surfaces. The comp utational cost is very low.