volume | PIER Journals

Abstract

A highly efficient Doherty power amplifier (DPA) using shunted reactive load is designed to achieve wideband operation. For enhanced back-off efficiency over the whole bandwidth, a modified load modulation network (LMN), which employs a shunted reactive load at the combining point, was firstly designed to enlarge the effective load impedance of the carrier amplifier at low and high frequencies. Then, the two-point matching approach was employed to design the carrier and peaking output matching networks, which can eliminate the use of offset lines and simplify the LMN. Measurement results show that the designed DPA can deliver an efficiency of 48%-61% at 6 dB back-off power over the frequency band of 2.2-2.9 GHz. For a 20 MHz LTE modulated signal, an average efficiency of higher than 55% can be achieved at an average output power of 37 dBm, while the adjacent channel leakage ratio is below -49 dBc after linearization.

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Dr. Wa Kong

Dr. Jing Xia

Dr. Da-Wei Ding

Dr. Li-Xia Yang

Dr. Chao Yu

Dr. Yongzhao Zhan