Improved linearity of power amplifier GaN MMIC for Ka-band SATCOM

The linearity performance of a Ka-band power amplifier (PA) GaN MMIC with a novel balanced 4-way combiner is presented. The 32 – 38 GHz two-stage PA produces a maximum power of 6 watts for class-A bias. Improved linearity is demonstrated by biasing the first and second stages in deep class AB, and class A, respectively. This improvement in overall linearity is achieved as the gain expansion of the first stage is balanced by the gain compression of the second stage. Measured linearity performance is presented.