Design of a high-efficiency GaN HEMT RF power amplifier

Highly efficient radio frequency power amplifiers are essential in modern wireless transmitter systems. This paper presents the analysis, design and simulation of a 2GHz high-efficiency class-J RF power amplifier for wireless communications. A commercially available RF power 6W Gallium Nitride high-electron-mobility transistor is used as the core of the amplifier. By optimizing the load impedance up to the third-order harmonic, the needed output voltage and current waveforms, which are desired according to the class-J operation mode, are realized. The simulated maximum power-added-efficiency reaches 77.1% with output power of 40.5dBm at input drive of 27 dBm. Through simulations it also shows that high efficiency is sustained during a bandwidth of 200-300 MHz.