Abstract
In this article, characteristics of circular waveguides filled with metamaterials are studied. Also, for the first time, hybrid modes are investigated, and several new conclusions in hybrid mode behavior are drawn. Particularly, conditions under which the hybrid mode separates into the transverse electric and transverse magnetic (n = 0) modes are obtained. This condition eases mode excitation in the waveguide without power being coupled to the undesired modes. Frequency dispersive behavior of the modes under isotropic conditions is addressed with potential applications. The anisotropic implementation, which offers a good technique for the practical realization of metamaterial-filled circular guides, is also investigated.