Method for Electromagnetic Property Extraction of Sublayers in Metal-Backed Inhomogeneous Metamaterials

A scattering (S-) parameter method has been proposed for electromagnetic property extraction of a target layer within metal-backed inhomogeneous metamaterial (MM) structures. It relies on recursive S-parameters for two different polarizations (parallel and perpendicular). Two different algorithms depending on the value of the incidence angles were proposed to add flexibility to our method. The algorithms were first validated by a metal-backed quasi-one-port method applicable only for one-layer (homogeneous) samples. Then, they were applied to extract electromagnetic properties of the split-ring-resonator-wire MM slab of a metal-backed two-layer inhomogeneous structure and the Omega MM slab of a metal-backed four-layer inhomogeneous structure, and extracted properties by our algorithms were compared with those retrieved by different methods applicable for homogeneous samples only. The accuracy of our method was also examined when there was some noise in S-parameters, when there was a misalignment in incidence angles, and a when large value of iteration number was used.