An Analysis of the Mutual Coupling between Antennas on a Smooth Convex Surface.

摘要

A simple, approximate, asymptotic high frequency result is developed in this paper for the electromagnetic surface fields excited by infinitesimal electric or magnetic current sources which are placed on a smooth, perfectly-conducting convex surface of any shape. These surface fields propagate along Keller's surface ray paths, and their asymptotic description is uniformly valid along the ray including the immediate vicinity of the source. Furthermore, as the curvature of the surface becomes vanishingly small, this result recovers the known, exact result for the fields on a planar, perfectly-conducting surface. The development of this result is heuristically based upon the form of the asymptotic solutions for the surface fields which are first obtained for the canonical circular cylinder and spherical geometries. These solutions are then generalized to the arbitrary convex surface via the local properties of wave propagation at high frequencies. The effect of torsion associated with the surface rays is clearly identified in this result through the presence of a factor T/k, where T is the surface ray torsion and k is the surface curvature along the ray direction. Some currently available numerical results based on this analysis are indicated for the circular cylinder case.