A high power on-wafer pulsed active load pull system

An on-wafer load pull system that is capable of measuring load pull contours on true high-power and large-periphery devices is described. Measurements are made under low-duty-cycle pulsed DC and RF conditions to minimize the effects of heating due to power dissipation in the on-wafer environment. With the current implementation of the load pull system, any load impedance on the Smith chart can be presented to the output of 4-W devices. The system is fully error corrected for reflection coefficient, transmission coefficient, input power incident, input power delivered, and output power delivered. The system is capable of automatic control and measurement by means of an HP 9000 series workstation. Data taken on C-band MMIC (monolithic microwave integrated circuit) power amplifiers and 2-mm GaAs FETs are presented. >