The research topic material characterization deals with the development of methods for determining dielectric material properties in the microwave range and examines the implementation of the methods in measurement systems. The characterization of the dielectric properties of liquid media such as oil, as well as ceramic or organic materials and composite materials are examined. The processes that have already been developed are characterized by the fact that the material parameters sought can be determined in the course of calibration measurements. The material parameters can be determined very efficiently and without complex calibration of the complete measuring system, so that in-situ measurements are also possible. The methods are also very robust. In addition to the theoretical derivation of the procedures and their simulation-based verification, measurement systems are implemented for both the free space and the measurement of liquids, with which the practical implementation can be demonstrated. Such calibratable measuring systems are of great interest for industrial applications, on the one hand for applications in open space, in which the material parameters are to be measured without contact and with high accuracy, and on the other hand for the material characterization of liquids, in which the medium to be examined is continuously passed through the measurements during the measurements Measuring probe or, for example, a pipeline can continue to flow.