X-parameter measurement challenges for unmatched device characterization

Abstract

X-parameter technology provides simulation-based design of non-linear circuits with inherent accuracy that is attributed to measurement-based model extraction. Recent advancements have combined Non-linear Vector Network Analyzer measurements with impedance tuners to compliment the equivalent accuracy of load-pull measurements with the analytic convenience of equation-based large-signal models. This paper investigates the challenges incurred when modeling high-power transistors under variable complex impedance matching conditions. It also compares the predicted performance of the X-parameter model against an independent large-signal model provided by the manufacturer for a 10W transistor. The results show a good correlation between the two models when compared under load-pull impedance modulation.