Ray-diffraction method for handling complex incident fields

A ray-diffraction method is described which is applicable to diffraction problems where the incident field on a diffracting edge cannot be represented as a single incident ray but exhibits a more complex form. The complex incident field may be represented by a combination of simple rays; the diffraction of each ray may then be treated individually. The total diffracted field is the sum of these diffraction components. The method is illustrated by applying it to the double knife-edge problem.