Ferrite-based phase shifters design: The modeling problem of non-saturated anisotropic ferrites

Modeling the microwave behavior of ferrite in a non-saturated state is a burning issue for ferrite phase shifter designers. In this paper, a WR-90 waveguide loaded by a ferrite slab is studied. Classical simulations, using the Polder tensor, are not consistent with the measurements even in the case of a totally saturated state. An improvement was observed by using a generalized permeability tensor model, enhanced by taking into account an extra dynamic demagnetizing field.