A Bias Tee for Broadband Measurement of Power Electronic Components

Bias tees are an important tool for many applications including vector network analysis. When trying to measure power electronic components with large DC currents and voltages at low frequencies, however, one quickly encounters the limits of the devices of common manufacturers. As accurate understanding and modeling of power electronic components becomes increasingly important for the study of their electromagnetic emissions, so do broadband measurements with bias tees. This paper describes the composition of such a special bias tee in terms of the necessary geometries and circuitry. Measurements of the characteristics of the presented tee show good results in a frequency range from 9 kHz to 500MHz at DC currents up to 10A (30A for a short time) and voltages up to 500V. Vector network analysis of passive filter structures under load thus also becomes possible for power electronic components in a broad frequency range.