Material characterization through a full-wave approach based on the BI-RME method

A numerical technique particularly suited for the determination of the dielectric properties of materials is proposed in this paper. The method combines the Boundary Integral-Resonant Mode Expansion (BI-RME) method and the segmentation technique. The circuit used for the unknown sample testing is segmented into homogeneously-filled building blocks. The admittance matrix of each building block is represented through a pole-expansion, and the electrical properties of the material appears explicitly in this expression. Therefore, when using an iterative process as discussed in this paper, the identification of the unknown electrical characteristics of the material does not require repeated full-wave analyses but only circuital matrix recombination. A simple yet meaningful computational example is reported, consisting of a waveguide with a pipe for the characterization of fluids or powders, which demonstrate the effectiveness of the proposed approach.