Design of Broadband High-Efficiency Load-Modulated Balanced Power Amplifier Based on Phase Control

This letter proposes a phase compensation method to design a broadband load-modulated balanced power amplifier (LMBA). Through the modeling and analysis of the output matching network (OMN) of the balanced amplifier (BA), the phase conditions for achieving optimal load modulation and mitigating control amplifier (CA) overdrive phenomena are derived. Meanwhile, a targeted phase compensation network (PCN) is designed to accurately meet the phase requirements obtained from the aforementioned analysis. Based on this phase control method, a broadband high-efficiency LMBA operating at 1.5–2.6GHz is fabricated and measured. The prototype achieves a peak output power of 42.8–44.8 dBm, with drain efficiency (DE) of 45.9%–69% at peak power and 45%–54.4% at 12–14-dB output back-off (OBO). Under the excitation of a 20-MHz 5G new radio (NR) signal with a 10-dB peak-to-average power ratio (PAPR), the adjacent channel power ratio (ACLR) decreases to below −46.7 dBc after digital predistortion (DPD).