Simultaneous AM-AM/AM-PM distortion measurements of microwave transistors using active load-pull and six-port techniques

A programmable active load-pull measurement system using two six-port reflectometers and three passive two-port standards has been developed to obtain load-pull contours of the transistor's input-output phase shift variations over a wide dynamic range of the input power. The output power, gain, power-added efficiency, and phase shift are measured simultaneously at the transistor's input and output reference planes. The phase distortion versus input power, /spl phi//spl sim/P/sub in/, and the AM-PM conversion coefficient at various power levels, k/spl sim/P/sub in/, are obtained for different load impedances by post-measurement calculations. A NE8001 MESFET is tested at f=1.7 GHz for the class A operation. The experimental results are also given.>