Broadband Waveguide Characterization of 3D-Printed Anisotropic Dielectric Crystals

Additive manufactured structured dielectrics with engineered permittivity tensors are promising tools for novel microwave components and are drawing increasing attention from researchers. However, design modeling and experimental verification of anisotropic materials are challenging and have not yet been thoroughly explored in the literature. In this work, a design approach based on superimposed spatial harmonics for the design of anisotropic lattices called dielectric crystals is used. Furthermore, the plane wave expansion method (PWEM) is identified as a powerful tool for modeling the effective permittivity tensor. A wideband material characterization measurement setup based on rectangular waveguides is utilized for experimental verification. Experiments with uniaxial anisotropic dielectric crystals are carried out and are shown to be in satisfying agreement with our theoretical modeling.