Design of 3.5GHz Linear High-Efficiency Doherty Power Amplifier with Pre-matching

摘要

In this paper, we analyze the shortcomings of traditional Doherty power amplifier (DPA) structure and propose an improved load modulation structure; Improving back-off efficiency of Doherty amplifier by using pre-matching technology. Also, the linearity is improved by using the in-band error cancellation technique of the Doherty amplifier. We implemented a Doherty amplifier with Cree's 10 W GaN HEMT transistor as carrier amplifier and peaking amplifier, respectively. At 3.5 GHz, saturated output power of the DPA is more than 43 dBm, saturated drain efficiency is greater than 75%; Under two-tone signal spacing by 5 MHz interval testing, drain efficiency of 6 dB back-off is greater than 50%, and IM3 is less than 30 dBc.