An iterative approach to scattering by edges and wedges

A new approach to the calculation of the scattering of waves by the edge of a thin plate or the edge of a wedge of any angle is presented. It has a number of advantages relative to previous methods. It is intuitively easy to grasp, being close in spirit to ray optics methods for solving problems. It deals with the whole range of configurations in the one way, rather than the patchwork of ways that has evolved in the past. It provides extremely good approximate solutions with minimal effort. The mathematics involved is reasonably simple. It promises to be applicable to a range of problems which have yet to be solved by other methods. In particular, we show how it can be applied in principle to obtain successive approximations to the solution of the problem of diffraction by a permeable wedge, where its relationship to the ray optics method is very clear.