18-W three-way Doherty amplifier for 5G applications

A new design configuration using three-way Doherty power amplifier targeting 3.4–3.8 GHz for 5G applications is designed using three 6W GaN HEMT transistors to achieve an 18W peak power. In this design, a new impedance modulation configuration is used, where the amplifiers are designed to achieve 13 dB of gain over the design band. Changing the location of the peaking amplifier or changing the operation sequence of the peaking amplifier can achieve good efficiency at the back-off region; however, the phase difference should be compensated at the input side of each amplifier. In addition, the performance variation of the designed amplifier was tested for different VSWRs taking into account the antenna impedance changing due to beamforming. There was an average of 2.2 dBm variation in the output power and 22% efficiency variation for different VSWRs at both the peaking and back-off regions.