Double diffraction at a pair of coplanar skew edges

A high-frequency solution is presented for the scattering in the near zone by a pair of coplanar skew edges when they are illuminated by a source at a finite distance. The solution is obtained by using a spherical-wave spectral representation of the first-order diffracted field from each edge. The final closed-form asymptotic solution includes terms up to the second order. It is shown that this second-order contribution is of the same order as the first one in overlapping transition regions. Moreover, the solution is cast in a convenient form, which is also directly applicable to treat the case when the two edges share a common face for both soft and hard boundary conditions. By choosing appropriate reference systems, the formulation for the scalar case is directly used to construct the solution of the more general electromagnetic problem for an arbitrarily polarized incident field. Numerical results are presented and discussed.