Design of Reconfigurable Broadband Doherty Power Amplifier Based on GaN

The bandwidth of traditional Doherty amplifiers is limited by the phase shift of the λ/4 transmission line at different frequencies. In this paper, a reconfigurable wide-band Doherty power amplifier (DPA) based on gallium nitride is designed. PIN switch is used to switch the peak power amplifier branch, and the phase shift range generated by the λ/4 phase compensation line is relatively reduced, thus effectively improving the bandwidth of DPA. In addition, harmonic suppression network is introduced into the output matching network of the peak power amplifier branch to improve the efficiency of DPA. To verify the validity of the design, a wideband high-efficiency DPA is designed and fabricated using gallium nitride high electron mobility transistors CGH40010F. The test results show that in the band of 2.8 GHz~3.6 GHz, the saturation output power is 42 dBm ~44.7 dBm, the saturation drain efficiency is 59.4%~69%, and the drain efficiency is 41.3%~48.8% when the power is backtracked by 6 dB.