Circular Polarization in Parallel Plate Waveguides

Counterrotating magnetic fields occur in fact naturally on either side of the symmetry plane of an ordinary rectangular waveguide propagating the dominant TE mode: at the interface and everywhere outside two different dielectric regions. Natural regions of circular polarization may be found in a rectangular waveguide propagating the dominant TE
₁₀
mode. This feature is particularly important as a number of nonreciprocal ferrite devices rely on this type of polarization for their operation. The polarizations along such a waveguide are in opposite directions on either side of the center line of the waveguide. Dielectric loaded parallel plate waveguides with open sidewalls or with electric or magnetic sidewalls all support, under appropriate boundary conditions, planes of circular polarization at the boundaries between the dielectric and air regions.