Waveguide circuits loaded with ferrite

The properties of waveguide circuits loaded with ferrite in the region bifurcated by a sheet dividing equally the broad wall of a lossless rectangular waveguide operating only in TE(NO) modes are discussed analytically with a view to designing waveguide filters. Slabs of polycrystalline garnet type ferrite magnetized in the direction of electric field are placed symmetrically in the bifurcated region of the waveguide having a metal sheet. These filters show the characteristics of frequency dependence on the value of an applied dc magnetic field. Using the quasi-isotropic approximation to the tensor permeability of ferrite, the analytical solution to these waveguide circuits can be obtained. Computed values are compared with experimental data. Application of the result to bandpass filters is described.