Highly efficient GaN-HEMT power amplifiers at 3.5 GHz and 5.5 GHz

This paper reports the design, implementation, and experimental results of two high efficiency GaN-HEMT power amplifiers (PAs) at 3.5 GHz and 5.5 GHz. A bare-die approach is used to eliminate package parasitics in conjunction with an in-house transistor model that enables investigation of the transistor intrinsic waveforms. With this as a basis, harmonic source-pull/load-pull simulations have been used to design and implement two state-of-the-art highly efficient harmonically tuned PAs. For the 3.5-GHz PA, large-signal measurement results show a PAE of 80%, a power gain of 15.5 dB, and an output power of 7 W, while for the 5.5-GHz PA, 5.6 W output power, 12.5 dB power gain, and 70% PAE are achieved.