Highly efficient and wideband harmonically tuned GaN-HEMT power amplifier

In this paper, the design of a highly efficient 25 W GaN-HEMT power amplifier (PA), operating in 1.7 - 2.3 GHz, is presented. The influence of the harmonics and the impact of the parasitic components of the nonlinear device are considered in order to ensure an accurate matching network design to achieve high efficiency. Optimum fundamental and harmonic load impedances were obtained using load-pull simulations across the operation band. From continuous wave large-signal measurements, an average output power of 44 dBm was obtained over the bandwidth. The corresponding drain efficiency ranged between 73 - 80 % with a gain of 12 dB. Linearized modulated measurement, using 10 MHz LTE signal with 7.3 dB peak-to-average-power-ratio (PAPR), shows an average power-added-efficiency (PAE) of 38.2 % and adjacent channel leakage ratio (ACLR) of almost -45 dBc at 1.8 GHz.