Electromagnetic properties measurements of ferromagnetic materials using microstrip

A broadband technique for the simultaneous measurement of the complex permittivity and permeability of film-shaped ferromagnetic materials is presented. Complex permittivity and permeability are computed from S-parameter measurements under a constant exterior magnetic field of microstrip transmission lines used as cells. Moreover, a simple and fast technique that allows to the measurement of magnetic materials with a low permeability is presented. The measurement bench uses a vector network analyzer, a high-quality on-microstrip test fixture, and an electromagnet. Measurements in the 0.05-20 GHz range show the validity of these methods.