A GTD Analysis of the Radiation from Slots in Planar and Cylindrical Perfectly-Conducting Structures with a Surface Impedance Patch.

Radiation by Sources on Perfectly Conducting Convex Cylinders with an Impedance Surface Patch.

“…It is noted that an Elliot mode can be excited by a magnetic line source if the surface impedance is inductive; whereas, it can be excited by a magnetic line dipole source if the surface impedance is capacitive. This present work represents an important extension and generalization of some of the earlier work [2,4,5]. The earlier approach by Pathak[4J which led to a preliminary, asymptotic solution, for this problem could be designated as the diffraction coefficient or the geometrical theory of diffraction approach (GTD).…”

“…The work based on the GTD approach in [4] is an extension of the GTD solution of Hwang, Kouyoumjian and Pathak[61 for analyzing the radiation by a magnetic line source on a perfectly conducting box that is partly covered by a finite dielectric panel (over the face on which the source is located). In contrast to the work of Hwang et al [6], a GTD analysis of the curved geometry in Figure 1 requires the solutions to more and different canonical problems, because of the complexity introduced into the analysis by the presence of the curvature.…”

“…A uniform asymptotic solution of an appropriate canonical problem which would lead to such a uniform diffraction coefficient is somewhat complicated and is not attempted at the present time. The GTD technique presented in [4] is thus useful for sufficiently large cylinders with a sufficiently long impedance patch on which an Elliot mode can establish itself. It is noted that a pure Elliot mode is established beyond a certain minimum launching distance on the impedance patch.…”

“…It is noted that like the SCIM, the MM-GTD and GTD formulations are also asymptotic in the sense that they are developed for electrically large cylinders. The MM-GTD and the GTD formulations are discussed in detail elsewhere [2,4] and some of the main features of these methods have been discussed in Chapter I, hence only a short summary of these methods will be repeated here for completeness.…”

“…The direct (or geometrical optics) ray field and the fields diffracted from the edges of the patch are calculated from appropriate canonical problems for TM and TE cases as explained in [4]. It is noted that the GTO solution pfesented in [4] is restricted to only those impedance surfaces which can support an Elliot type surface ray mode field.…”