Advances in microwave characterization of materials

Advances in microwave material characterization using transmission line and free space techniques are presented. Single-coil perturbation measurement of thin ferromagnetic films is studied. International cross-measurements provide a first step in the technique validation. By the design of new reference samples based on meta-materials, we improved the apparatus calibration process. As magnetic materials may be mechanical stress sensitive, we developed coaxial cells to measure the permeability spectra of ferrite under compressive stress. Experimental validation of the cells is presented. Finally, a microwave near-field measurement technique is used to obtain a non-destructive imaging of material properties. We demonstrated the ability of our approach to detect and quantify local dispersions of electromagnetic properties.