DIFFRACTION BY A WEDGE WITH HIGHER-ORDER BOUNDARY-CONDITIONS

This paper presents a powerful analytical procedure that combines the higher-order boundary condition approximation and the modified Malyuzh inets technique to treat electromagnetic scattering from arbitrarily a ngled wedge-like composite configurations with penetrable faces. The c onfiguration may be either a perfectly conducting wedge covered with a dielectric/ferrite material or a composite wedge with strong lar abso rbing faces, so that the field transmitted directly through the config uration can be neglected. With special emphasis on retaining the passi vity of the media interfaces, boundary conditions on the wedge faces a re approximated using impedance conditions with higher-order field der ivatives. To close the formulation of the diffraction problem, a class of contact conditions is described that ensures the uniqueness and re ciprocity. A general solution which is valid for passive boundary cond itions of arbitrary odd orders is derived in an explicit form as the S ommerfeld integral involving: arbitrary constants. By choosing these c onstants in such a way as to fit its analytical behavior for kr much l ess than 1 to the exact one obtained by directly integrating the Maxwe ll equations, a specific form of the contact conditions can be deduced that reflects the design features of the configurations near their ed ges and forces the solution to be an asymptotic one for vanishing: thi cknesses of the coatings or skin layers. As a result, the unique and r eciprocal closed-form solution associated with third-order boundary co nditions is presented which uniformly describes the diffraction of an H-polarized plane electromagnetic wave by a variety of the composite w edge-like structures with penetrable faces, extending thereby Malyuzhi nets' solution for an impedance wedge to more sophisticated boundary c onditions.