Advanced computational methods for analysis of the circular waveguide completely filled with azimuthally magnetized ferrite: Review of recent results

A review of some of the modern methods for investigation of the phase behaviour of the azimuthally magnetized circular ferrite waveguide, under normal TE_0n modes excitation, is presented. The debate is focused on two numerical techniques, based on the boundary-value problem approach and using the complex Kummer confluent hypergeometric function Φ(a, c; x) of specially selected parameters and variable as wave function for propagation. The key point in both of them is the repeated application of an iterative procedure, yielding the positive purely imaginary roots of the structure´s characteristic equation, written in terms of Φ(a, c; x), for a varying imaginary part of the complex parameter a of the same. The first of the schemes allows to obtain the phase portrait of the geometry in the r̅₀ - β̅ plane (the β̅(r̅₀) - phase characteristics with α as parameter) and the second - its portrait in the |α| - β̅ one (the β̅(|α|) - modified phase curves with r̅₀ as parameter) where r̅₀ and β̅ are the normalized in an appropriate way guide radius and phase constant of the wave and α is the off-diagonal ferrite permeability tensor element. The two types of lines are plotted, talked over and juxtaposed. The areas of wave transmission in each of the cases are pictured, as well. The main result of the study is that the change of the direction of magnetization of the anisotropic load is the most important factor that determines the kind, the limits and the shape of the domain in the r̅₀ - β̅ and |α| - β̅ phase plane, resp. in which the mode inspected might be sustained.