Wideband RF characterization setup with high dynamic range low frequency measurement capabilities

In this paper, a wideband RF characterization setup with low-frequency (LF) measurement capabilities is presented. Simultaneous LF and RF measurements enable studies of trapping phenomena, thermal effects and other LF-related nonlinear distortion in microwave devices using realistic wideband RF stimuli. The setup is capable of measuring up to 4 GHz through the RF path, and from DC to 125 MHz through the LF path. A study is made on how device linearity is affected by the choice of power supply unit (PSU). LF measurements reveal significant differences in baseband termination in the PSUs, consequently affecting the linearity of the measured RF output spectrum.