Mode-matching analysis of H-plane ferrite-loaded rectangular waveguide discontinuities

Abstract

The full set of eigenmodes existing in a ferrite-slab-loaded rectangular waveguide is first obtained and then used to compute the scattering matrix of a junction between an air-filled rectangular waveguide and an H-plane ferrite-slab-loaded rectangular waveguide by using the mode-matching method. Numerical results for the scattering parameters of the H-plane waveguide discontinuity are compared to experimental data and those obtained by Ansoft's HFSS. Good agreement is observed. To demonstrate the usefulness of this structure, a computer-optimized 90°nonreciprocal phase shifter is designed using an H-plane ferrite-slab-loaded waveguide. With only one-step impedance matching sections at both ends of the ferrite slab, a compact design is achieved to have 2°phase error and less than ؊30 dB return loss over about 5% bandwidth.