A Study on GaN MMIC Power Amplifier Stability-Performance Design Tradeoffs at X Band

This work presents a measured comparison of two MMIC power amplifiers (PAs) that have nearly the same design except for different degree of on-chip stabilization. In MMIC design, it is often necessary to overdesign stability because of the difficulty of post-fabrication correction, but this comes at the cost of in-band RF performance. As an example of this tradeoff, we compare two different X-band MMIC PAs, one of which is unstable without off-chip capacitance. The less stable design exhibits 0.58 dB higher gain and 3.4 percentage point higher efficiency at the design frequency of 10 GHz.