Cut-off frequencies of magnetoplasma slab-loaded waveguides using an iterative finite element method

An iterative finite element method is introduced to calculate the cut-off plane of slab-loaded magnetoplasma waveguides. As the slab filling ratio increases, both the modal cut-off numbers and the singlemode bandwidth reduce. Overmoding is predicted if the bias field is chosen such that the extraordinary wave resonance falls within the waveguide frequency range. Split cut-off numbers are indicative of increased nonreciprocity in the propagation constants. From an investigation of the propagation constants, specific structures and bias conditions are recommended for the development of isolators and differential phase shifters in the frequency range 190-460 GHz.