Measurement of anisotropic material properties for antenna applications

The anisotropic behavior of engineered materials is not often taken into account in the design of antennas, usually because the material properties are not well characterized. In this paper, a step is taken toward the measurement of the anisotropic properties of materials by developing specific methodologies for the characterization of biaxially anisotropic and gyromagnetic materials. These techniques compare the measured S-parameters of samples placed into rectangular waveguides to theoretically computed S-parameters to characterize the material. The theoretical S-parameters are calculated via a mode matching technique and inversion is performed using an iterative solver.