Characterization of Biaxial Anisotropic Material Using a Reduced Aperture Waveguide

A technique is introduced for measuring the electromagnetic properties of a biaxial anisotropic material sample using a reduced-aperture waveguide sample holder designed to accommodate a cubical sample. All the tensor material parameters can be determined by measuring the reflection and transmission coefficients of a single sample placed into several orientations. The theoretical reflection and transmission coefficients necessary to perform the material parameter extraction are obtained using a modal analysis technique. An optimization method that seeks to minimize the difference between theoretically computed and measured reflection and transmission coefficients is used to perform the extraction. Measurements of a stacked dielectric medium is characterized to demonstrate feasibility of the reduced-aperture waveguide approach.