Excitation of modes guided by a cylindrical channel in a lossy gyrotropic medium

A study is made of the excitation of electromagnetic waves by a given ring electric current in a lossy gyrotropic medium containing an inhomogeneity in the form of a cylindrical channel capable of guiding the excited waves. The channel is aligned with the gyrotropic axis of the medium. It is shown that under certain conditions, dissipative losses in the gyrotropic medium can lead to a substantial redistribution of the source radiation power over the spatial spectrum of the modes guided by the channel compared with the case of a lossless medium. Numerical results are presented that illustrate these changes in the efficiency of excitation of the guided modes.