C-Band High Efficiency GaN HEMT Power Amplifier with Harmonic Tuning

In this paper, the design and measurements of a 5-6GHz high-efficiency MMIC high power amplifier implemented in a $\mathbf{0.25}\mu\mathbf{m}$ GaN HEMT process was described. The MMIC has been designed using 2-stage topology. At 5-6GHz, the MMIC showed a power-added efficiency (PAE) of 44%-52% with an associated gain over 20dBm and an output power of 35dBm. The MMIC achieved above 50% PAE at 5.3-5.6GHz. The key to this design is determining and matching the optimum source and load impedance for PAE at the first three harmonics in output stage in order to improve the PAE.