4-port vector network analyzer

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With respect to technological progress, compact multi-port systems operating at increasing frequencies with multiple transmit and receive channels in a miniaturized setup can be realized. Some prominent examples for frequencies at about 100 GHz are radar based sensor systems as needed for autonomous driving or for measurement systems in industrial process industry. High frequency high precision measurement techniques are one of the main research topics of the chair for high frequency systems. Actual research projects are concerned with the calibration of multiport network analyzers with a focus on the investigation of self-calibration methods, alternative error models and an efficient choice of networks for calibration. In addition, methods for material characterisation and for imaging purposes based on MIMO-systems (multiple input multiple output) as well as radar sensors are investigated.For research in the field of multiport vector network analyzer calibration, the measurement system as applied for, is of significant importance. Partially, the analyzer on its own with its internal architecture even becomes an object of investigation. Actually, it was only possible to verify the theoretical research results by measurements with a multiport network analyzer up to 40 GHz. This measurement system was a prototype setup, which was made available for the researcher restricted in time for one year. The system is no longer available now. In order to be able to continue research work in this field and with respect to actual international research topics to increase the frequency range up to 110 GHz, the 4-port vector network analyzer as applied for is strongly needed. For research in the field of electromagnetic material characterization the measurement of the material properties is essentiell, because the relative permittivity as well as the loss of the material are generally frequency dependent. For this purpose, a large frequency bandwidth as being supported by the measurement system applied for, is of high interest, because this enables the investigation of innovative methods for signal analysis for material characterization. In this way spectroscopic analysis can be studied, this means methods that use the characteristic frequency behaviour of the material for unique identification. Furthermore, methods in time domain can be examined advantageously, because due to the high bandwidth a high resolution in time can be achieved for the measurements. In addition, the setup is very attractive for the investigation of imaging methods based on focussing antennas, mirrors or post-processing algorithms which can be applied. Thus, the representation of the material characteristics with a spatial resolution for the identification of inhomogenities, inclusions or thermal alteration becomes possible. Further on, ellipsometric methods, based on transmission and reflection measurements with different polarisations can be investigated in parallel.