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, φ~P_in, and the AM-PM conversion coefficient at various power levels, k~P_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