DIFFRACTION BY A SYMMETRICAL MATERIAL JUNCTION SIMULATED WITH GENERALIZED SHEET TRANSITION CONDITIONS

The diffraction by a material discontinuity in a thick dielectric/ferrite slab is a problem which is amenable to a treatment via the dual integral equation approach (a variation of the Weiner-Hopf method). However, the resulting solution displays unknown constants, characteristic of the incompleteness associated with the generalized transition conditions employed in modeling a thick slab. The constants can be shown to depend on the geometry and properties of the discontinuity, and this paper is concerned with their explicit determination by enforcing field continuity across the slab junction. This requires knowledge of the fields internal to the slab, which are not readily available since the Weiner-Hopf solution provides only the fields external to the slab. The major portion of this paper, therefore, is concerned with the determination of the internal field. This is accomplished by first expressing the field as an expansion of discrete and continuous eigenmodes valid in the exterior and interior slab region. The expansion or mode coefficients are then identified by recasting the Weiner-Hopf solution in a suitable form, enabling the solution constants to be numerically computed by matching the field expansions to the left and right of the slab discontinuity at a discrete set of points.