Calibrateable microwave and millimeter wave measurement techniques for contactless and nondestructive material characterizations

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The objective of this project is the development of calibrateable measurement techniques for contactless and nondestructive material characterization with microwaves and millimeter waves. Measurement techniques for the characterization of complex scattering parameters of two ports based on reflection measurements are to be developed. These measurement techniques are based on transmission measurements, in which the receiving antenna is replaced by active reflectors and passive reflectors, respectively. Additionally, this project aims at the development of calibration methods for free space applications. In this case, the project is mainly focused on the reduction of the necessary number of calibration standards. The aim is the development of calibration methods without the necessity of mechanical displacements during the calibration procedure. Within this project a change of the electrical length due to a small frequency shift is used for the realization of a calibration standard instead of a change of the mechanical length.For the development and the verification of the measurement techniques and the calibration procedures, respectively, comprehensive three dimensional electromagnetic simulations are applied. Thus, influences of the measurement system and the surrounding, which are realistically emulated, are taken into account. In addition to the detailed emulation of the measurement environment, the simulations are based on realistic error networks given by a network analyzer. Based on the electromagnetic simulations serveral measurements campaigns for the verification of the developed measurement techniques are performed.Furthermore, fundamental considerations on the suitability of FMCW radar systems for material characterization in the frequency domain are performed.