Utilization of 3D simulators for characterization of dielectric properties of anisotropic materials

The principles for utilization of the electromagnetic 3D simulators for determination of dielectric constant and loss tangent of anisotropic materials by microwave cavity resonators are described. Two-resonator method (described elsewhere) based on TE₀₁₁-mode and TM₀₁₀-mode resonators with disk-shape sample is applied for separate measurement of the longitudinal and transversal dielectric parameters. Results for isotropic material (polycarbonate Lexan® Exell D sheets) and for anisotropic material (RO4003 substrates) are presented in the paper in order to compare the accuracy of three different cavity models - perturbation models, analytical dispersion equation models and 3D simulator models. The applicability of the measurement method is discussed and some limitations are formulated concerning the separate determination of longitudinal and transversal parameters of anisotropic substrates.