An asymptotic solution for the diffraction by a discontinuity in curvature coupled with surface diffraction

An extension is developed for the asymptotic theory of electromagnetic diffraction by a discontinuity in curvature on a smooth convex perfectly-conducting surface. It covers the case where the rays incident on and diffracted from the discontinuity are nearly tangent to the surface or are creeping rays, so that surface diffraction is involved. This extension is restricted to those diffracted rays lying on the same side of the discontinuity as the incident ray; this includes backscatter but excludes forward scattering.