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

摘要

The radiation from a slot in an electrically large, perfectly conducting cylinder partly covered with an impedance surface is treated by a combination of the geometrical theory of diffraction (GTD) and the method of moments (MM). The method is far more efficient than MM solutions of conventional integral equations because a perturbation type integral equation which requires the unknown to be evaluated only over the impedance patch is employed in the present analysis. Furthermore, the GTD method can be systematically incorporated into this perturbation integral equation not only to provide substantial simplifications in the solution, but also to directly treat convex cylinders of variable curvature. Numerical results are presented for the two-dimensional circular cylinder case for different size cylinders, different surface impedance values, and for different size surface impedance patches. The radiation from slots in an infinite, planar perfectly-conducting surface which is partly covered with an impedance surface is also analyzed via the MM-GTD solution of the same perturbation type integral equation as in the cylinder case. A comparison of the antenna pattern calculations for the planar and cylindrical configurations indicates the effects of surface curvature especially in the region of space in which the slot is directly visible. (Author)