Topics in Guided Wave Propagation Through Gyromagnetic Media: Part II - Transverse Magnetization and the Non-Reciprocal Helix

1.1. General Remarks about Non-Reciprocal Propagation Part I of this paper began with a brief discussion of some of the microwave properties of two gyromagnetic media; the gas discharge plasma and the ferrite. The remainder of Part I was devoted to the analysis of the mode spectrum in a cylindrical waveguide filled with one of the media and placed in an axial magnetic field. It was demonstrated that the natural modes in such a guide are right- and left-circularly polarized waves which travel with different phase velocities. Accordingly a plane polarized mode, which to some approximation can be regarded as the sum of right and left circular modes, wall, in traversing a section of the guide, undergo Faraday rotation, just like a plane wave in the unbounded medium. It is true that the presence of the guide wall has a drastic effect on the course of the rotation with magnetizing field, changing it, sometimes beyond recognition, from that prevailing in the unbounded medium. Nevertheless the principle remains the same; confinement of the wave to a guide merely modifies quantitatively the Faraday effect for plane waves. In optics, where practically plane waves are almost always employed in this connection, the non-reciprocal nature of this effect is so familiar that it hardly requires restatement here. 939