A General Solution of the Thin Circular Loop Radiation

Abstract

Electromagnetics ISSN: 0272-6343 (Print) 1532-527X (Online) Journal homepage: http://www.tandfonline.com/loi/uemg20A general solution of the thin wire circular loop radiation is offered, without assuming a certain current distribution in advance. The solution is valid for any radiuswavelength ratio and for both near and far field. The field potentials are expressed through the general wave equation basis functions in spherical coordinate system. A zero electric field along the loop is achieved as a sum of the radiation field and time-independent excitation field. The unknown-expansion coefficients are found by the Galerkin method. For highly accurate fulfillment of the boundary condition only twelve modes were required. The current distribution was found uniform for a very small loop, but also close to uniform for certain much larger electric lengths. It was also found that in a far zone both E ϕ and E θ exist, with E ϕ being some ten times greater than E θ , if the source occupies a very small portion of the loop.