DIFFRACTION BY A PLANAR JUNCTION BETWEEN A PERFECTLY CONDUCTING AND APERIODICALLY LOADED IMPEDANCE SURFACE

By using a perturbative method, an integral representation for the fie ld scattered by a planar junction between a perfectly conducting and a periodically loaded impedance surface is determined, when the junctio n is illuminated by a plane wave perpendicularly incident on its edge. Both a uniform, asymptotic expression and a series representation are presented for the first-order perturbative correction to the field sc attered by the junction. The series representation is expressed in ter ms of Bessel functions of integer order and is suitable for field calc ulations at small distances from the edge. Several numerical results a re presented to demonstrate the applicability of the proposed techniqu e.