Broad-Band Measurement of all Complex Permeability Tensor Components and Complex Permittivity of Ferrites using a Rectangular Waveguide

Abstract
We have worked out a broad-band characterization method for magnetized ferrimagnetic materials. The technique is based on the reflection/transmission measurement of the S-parameters of a rectangular waveguide partly loaded with a ferrite that is to be characterized. The device is set in between the poles of an electromagnet to magnetize the sample. The fundamental principle of the measurement consists in using the anisotropy of the material to lead to the non-reciprocity of the cell (S₁₁ ≠ S₂₂ and S₂₁ ≠ S₁₂) in order to have the same number of information that for the characteristics we want to determine (complex permittivity and all complex permeability tensor components). In this paper, we will compare in the X-band (8 - 12.4 Ghz) the theoretical S-parameters of the cell with those measured by the network analyzer for different ferrites of well-known properties in order to validate the electromagnetic analysis of the cell. We will underscore the importance of the losses which are entirely responsible for the non-reciprocity of the S-parameters modulus. To conclude we will suggest a strategy to resolve the inverse problem with an optimization method.