FIELD OF A LINE SOURCE SITUATED PARALLEL TO A SURFACE-WAVE STRUCTURE COMPRISING A PAIR OF UNIDIRECTIONALLY CONDUCTING SCREENS

Abstract

The problem of radiation from an electric line source situated parallel to a surface-wave structure composed of a pair of parallel unidirectionally conducting screens is considered. The screens are conducting in directions making angles α and — α, respectively, with the x axis, while the line source is directed parallel to the γ axis and is located either above or between the two screens. The problem is resolved as the superposition of symmetrical and antisymmetrical sources, since either of the two surface-wave modes that can be supported on the structure is associated with an appropriate type of excitation. Both surface-wave modes are excited in the superposed case of a line source.The radiation field is evaluated and, under suitable conditions, is seen to exhibit sharp peaks. The correspondence of these peaks with complex poles in the integral representation of the field is demonstrated. It is further observed that, when the line source is situated above the structure, the amplitude of the field components in the lower half-space is independent of the location of the source, although the phase is affected. The surface-wave power is determined and it is shown that high values of launching efficiency are readily attainable.