Permittivity and permeability measurements of a thin film with patterned anisotropy at microwave frequencies

We propose a measurement technique to retrieve the constitutive parameters of a magnetic alloy composite in the form of thin film. Frequency of interest is 0.5 MHz-2.5 GHz, and the sample under test is patterned along the hard axis exhibiting in-plane anisotropy. To measure both the in-plane permittivity and permeability of the film, we prepare two separate planar transmission line fixtures, and then collect the transmission coefficient with the sample inserted in the fixtures. The in-plane permittivity and permeability are extracted from the transmission coefficient using a two-step retrieval process, namely, calculating the effective parameters out from the transmission coefficient and calculating the sample parameters out from the effective parameters. The latter is implemented by means of curve fitting a set of full-wave simulation data, instead of conventional quasi-static analyses, enabling broadband characterization in the microwave frequency range.