Tuning range analysis of load pull measurement systems and impedance transforming networks

This paper studies, by mean of a mapping between the Smith chart and impedance plot, the different aspects that impact the tunable range at the DUT reference plane in a passive load pull measurement system. The utilization of an impedance transforming fixture is considered and the technique to choose the right transformation ratio is presented. Finally, a method to encircle the absolute tunable region of a load pull system is explained, considering the use of any impedance transforming network.