Efficiency enhanced post-matching Doherty power amplifier based on modified phase compensation network

The post-matching (PM) topology is an effective approach to broaden the bandwidth of Doherty power amplifiers (DPA). However, its efficiency has been limited because previous works only considered the fundamental frequency termination, and not the harmonics. In this paper, a modified phase compensation network is used in the PM Doherty topology to realize a third harmonic open as viewed by both carrier and peaking device in the Doherty region. Hence, the efficiency enhancement in the entire Doherty region can be achieved. For demonstration purpose, a high efficiency Doherty prototype is devised based on two identical 10W GaN HEMTs. Measurement results show that at least 50% drain efficiency is achieved at 6 dB back-off power from 1.3 to 1.8 GHz.

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