A Time-Domain Vector Network Analyzer Suitable to Characterize Passive and Active Devices

This work presents the implementation of a Time-Domain Vector Network Analyzer (TD-VNA) that measures the S-parameters of passive and active devices using the time-domain waveform of the incident and reflected voltages measured with an oscilloscope. The calibration of the TD-VNA is fully compatible with traditional calibration techniques used in a Vector Network Analyzer. The proposed TD-VNA can measure small and large-signal S-parameters of a transistor, as well as the transistor's gain compression and output power and the magnitude and relative phase of the transistor's output spectral components, the latter being a feature not available in commercial VNAs. Experimental data from a microstrip low-pass filter and a GaAs FET ATF34143 measured with the TD-VNA and with conventional test systems show a correlation higher than 99.5%