In RF systems dielectric materials are not only mechanical but functional components, e.g. as substrate material for planar circuits, dielectric waveguides, RF-agile additive manufacturing or antenna radomes. For the computer aided design of such RF components the knowledge of the dielectric material properties in terms of the permittivity ($\varepsilon_\text{r}$) and loss tangent ($\tan_\delta$) are very important. The LHFT is constantly developing new setups for high precission material characterization in the microwave to THz frequency range to accommodate new materials and manufacturing technologies and processes.