A Non Destructive and Non Contact Technique to Characterize the Permeability of Shaped Material in the Microwave Range

A non-destructive and non-contact technique has been developed to control the microwave characteristics of a layer of magneto-dielectric material covering an object. The method assumes that one of the radioelectric characteristics is known with its uncertainty. The measured signal, reflected at the surface of an Object Under Test, is compared to a numerical calculation taking as input parametric variable the desired microwave characteristic, and then this one is determined by solving an inverse problem using the calculated and measured points. The evaluation of the uncertainties, then their calculation, and finally their analysis, are presented as well as measurement results on a flat magneto-dielectric sample.