Criterion for Phase Shifter Operation of the Circular Waveguide with Azimuthally Magnetized Ferrite and Dielectric

The criterion under which the circular waveguide, containing a co-axially positioned dielectric cylinder and latching ferrite toroid of azimuthal magnetization, acts as a nonreciprocal digital phase shifter for the normal TE₀₁ mode, is ferreted out. Employing it, a numerical method is elaborated that enables to reveal the impact of the material and geometry parameters of the transmission line considered on the width of the area in which it provides differential phase shift. The approach uses definite set of roots of the structure's characteristic equation, derived earlier by means of complex Kummer and Tricomi confluent hypergeometric and real zeroth and first order Bessel functions, and the real positive L̅_4± numbers, connected with other set of roots of the equation spoken of. For simplification it is assumed that the relative permittivities of the two layers are equal. Results are presented for a fixed value of the dielectric cylinder to guide radius ratio and a varying off-diagonal ferrite permeability tensor element.