Application Rules for Accurate IMD Characterization in GaN HEMTs

This paper presents a fully calibrated 2-channel frequency-domain measurement setup using VSA as receiver for characterizing nonlinear RF devices. This characterization system enables the acquisition and vector error-correction of complex traveling waves at the DUT reference plane. As an application example, 3.2 mm GaN HEMT is characterized under 2-tone and W-CDMA excitation. Influence of DC feed in device distortion behavior has been deeply investigated. Further, based on the experimental analysis, a simple bias tee is designed which can overcome improper DC feed conditions and tested through drain bias sensing on 0.5 mm GaN HEMT.