Advances in the theory of the circular waveguide with an azimuthally magnetized ferrite toroid and a dielectric cylinder

The domains of propagation, the phase characteristics and the lower and upper cut-off frequencies of the circular waveguide, containing a thin central dielectric cylinder, surrounded by a thick latching ferrite toroid, magnetized azimuthally to remanence, are studied for the normal TE₀₁ mode, assuming equal values of the relative permittivities of both strata. The main result of analysis is that the presence even of a tiny symmetric isotropic non-uniformity in the anisotropic medium around the axis alters completely the phase behaviour of the configuration, compared to the case in which the ferrite takes up the entire transmission line, discussed earlier. This is especially noticeable, if the sign of its magnetization is positive (counter-clockwise). Moreover, the change of the dimension of the inner layer, of its permittivity, preserving that of the outer one the same and of the direction of magnetization, are the most important factors that determine the position, borderlines, form and size of the area in the phase plane in which the wave might be supported, as well as the distribution of its two kinds of cut-off frequencies.