High-impedance transmission line with hybrid surface waves propagating near gyromagnetic resonance on a ferrite cylinder

This work presents a derivation of expressions for the electromagnetic fields propagating at a frequency near gyromagnetic resonance on a ferrite cylinder magnetized by an applied axial dc magnetic field. This system allows propagation by hybrid surface waves only, where the axial electric and magnetic fields are both nonzero. The expressions apply to the transverse impedance, the ratios of the electric field to the magnetic field for the radial and azimuthal components of these waves, and the power transfer impedance, which relates the axial current to the power transferred by these waves. Numerical values, based on the properties of strontium hexaferrite measured at 120 GHz, show that the power transfer impedance may exceed 1 MΩ. The data suggest that short lengths of such a high-impedance transmission line could be used to increase the output from millimeter-wave mixers.