Fundamental Wave Phenomena on Biased-Ferrite Planar Slab Waveguides in Connection With Singularity Theory

Abstract—In this paper, characteristic dispersion phenomena and interactions of the discrete surface- and leaky-wave modes supported by a grounded biased-ferrite slab waveguide are analyzed using singularity and critical-point theory. Surface- and space-wave leaky modes are studied for different orientations of the applied magnetic bias field. As the bias field is rotated away from a coordinate axis, the modes become hybrid, and mode cou-pling or modal degeneracies may occur. Mode coupling, in general, is governed by a Morse critical point (MCP), and the behavior of the MCP is found to be useful in explaining and predicting modal behavior on this complicated waveguiding structure. In addition, leaky-wave dispersion behavior and leaky-wave cutoff associated with a fold singular point is studied by varying the orientation of the applied magnetic bias field. Index Terms—Critical points, ferrite slab, leaky waves, mode coupling, singularity theory, surface waves. I