35 W bi-level supply modulated Doherty amplifier for 3G LTE base station

This paper presents a Doherty power amplifier (DPA) controlled by the optimized bi-level supply modulator to improve an overall efficiency. By utilizing the supply modulation method determined by the probability density function (PDF) of an interest signal, an estimated average efficiency can be improved as much as 8.5 % compared with that of conventional DPA. For the verification the proposed DPA using commercial 120 W GaN devices has been devised. The experimental results show that the proposed DPA delivers a drain efficiency (DE) of 53.8 % and power added efficiency (PAE) of 50 %, with a gain of 11.8 dB at an average output power of 34.7 W for a 2.65 GHz 10 MHz 3G LTE signal with a 9 dB peak-to-average power ratio (PAPR). The measure result reveals that the DE of proposed DPA is 6 % higher than that of conventional one.