An active pulsed rf and pulsed dc load-pull system for the characterization of power transistors used in coherent radar and communication systems

This paper presents a new automated and vector corrected active load-pull system allowing the characterization of microwave power transistors under coherent pulsed RF and pulsed DC operating conditions. Measurements of an S band-Class C-8 Watt silicon bipolar amplifier are shown and demonstrate the ability of our system to accurately characterize power variations and carrier phase shift within the pulse. Source and load-pull measurements of an 8/spl times/30 /spl mu/m/sup 2/ GaInP/GaAs HBT (Thomson LCR) are also reported for different pulse widths.