High-efficiency three-way Doherty power amplifier using reconfigurable PD

In this paper, a new reconfigurable power divider (PD) is proposed to improve the efficiency of the three-way Doherty power amplifier (DPA). The conventional lambda/4 transmission line is replaced by the proposed reconfigurable PD in the input of peaking amplifier, where the 90 degrees phase shift and impedance matching can be achieved. Furthermore, the output power distribution ratio (PDR) can be continuously adjusted in a large range by adjusting the reverse voltage of the varactor diodes. Therefore, the reconfigurable PD with the best PDR can assign input power to the peaking amplifier. Experiment results show that the maximum measured power added efficiency (PAE) of the proposed three-way DPA is 49%, which is improved by 5% compared with conventional three-way DPA.