Electromagnetic Wave Propagation Along a Ferrite Loaded Wire

The dispersion relation for axially symmetric modes propagating on a surface waveguide composed of a central conductor surrounded by an axially magnetized ferrite tube has been obtained. Tuning curves for an open boundary post resonator are calculated and compared with experimental results for an X-band tunable filter. The modes of circulation of a three-port waveguide circulator utilizing this geometry have also been studied and experimentally verified.