Extracting material constitutive parameters from scattering parameters

Abstract

In the frequency domain all materials can be described electrically by their complex permittivity and permeability. These constitutive parameters determine the response of the material to electromagnetic (EM) radiation. The precise knowledge of complex permittivity and permeability is required not only for scientific but also for industrial applications. Due to the uncertainties in manufacturing processes, often the only way to find a material's parameters is to measure them. The concept of metamaterials, exhibiting negative permittivity and permeability, is attracting a lot of attention. Such materials are also termed left-handed materials (LHMs). This thesis examines several methods to determine the effective permittivity and permeability of both normal materials and metamaterials. CST Microwave Studio is used to model the materials in both free space and rectangular waveguide environments to calculate the S-parameters (S11 and S21) from which the constitutive parameters can be extracted.