Hybrid-Frequency Cutoffs in Gyrotropic Waveguides (Short Papers)

The behavior of the Brillouin diagram ω versus β_z is analyzed for axially magnetized gyrotropic waveguides in the vicinity of the hybrid frequencies ω_k and ω_i. Starting from the exact dispersion relation for the modes in the waveguides under consideration it is shown that 1) the dispersion curves terminate at discrete cutoff points located along the ω = spl omega/_k, ω_i line and 2) the group velocity at these points is zero. These results modify the behavior of the dispersion curves existing in the literature.