Effects of drain current kinks and negative gate resistances on the performance of HFET MMIC power amplifiers

Using novel characterization techniques, frequency-sensitive gain/phase discontinuities of multi-stage MMIC power amplifiers were correlated with HFET drain current kinks and negative gate resistances. The correlation was explained in terms of hole-trapping and self-biasing mechanisms. A remedy involving bias-stabilization diodes was experimentally verified. Other possible remedies are also discussed.