等效跨导补偿的负载调制增强准理想Doherty射频功率放大器研究

华均; 许高明; 陈景豪; 陆思炀; 尤蕾渊; 吕言; 李刚; 史卫民; 刘太君

doi:10.11999/JEIT250789

等效跨导补偿的负载调制增强准理想Doherty射频功率放大器研究

doi: 10.11999/JEIT250789 cstr: 32379.14.JEIT250789

1.
宁波大学信息科学与工程学院宁波 315211
2.
重庆大学微电子与通信学院重庆 400044

详细信息

作者简介:
华均：男，博士生，研究方向为射频集成电路与系统

许高明：男，教授，研究方向为无线通信

陈景豪：男，博士生，研究方向为功率放大器非线性建模

陆思炀：男，硕士生，研究方向为射频功率放大器

尤蕾渊：男，硕士生，研究方向为射频功率放大器

吕言：男，博士生，研究方向为射频集成电路与系统

李刚：男，硕士生，研究方向为射频系统自动化测试与设计

史卫民：男，副教授，研究方向为射频集成电路与系统

刘太君：男，教授，研究方向为无线通信

通讯作者:
许高明　xugaoming@nbu.edu.cn

中图分类号: XXXX
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出版历程
- 修回日期: 2025-12-12
- 录用日期: 2025-12-12
- 网络出版日期: 2025-12-19

Research on Load Modulation Enhancement of Quasi-Ideal Doherty Power Amplifier with Equivalent Transconductance Compensation

1.
School of Information Science and Engineering, Ningbo University, Ningbo 315211, China
2.
School of Microelectronics and Communication, Chongqing University, Chongqing 400044, China

摘要

摘要: 现代无线通信系统对射频功率放大器在高动态范围的性能提出了严苛要求。Doherty功率放大器(Doherty Power Amplifier, DPA)虽然通过主功放与辅功放的动态负载调制显著提升了回退功率下的工作效率,但其工作在C类偏置下的辅助功放因导通特性不足，导致输出电流受限，从而引发负载调制偏差，进而制约其性能表现。本文针对辅功放电流输出能力受限的问题，提出了等效跨导补偿的概念，通过引入补偿支路，精准矫正了C类偏压下辅功放较弱的输出电流，从而实现准理想的动态有源负载调制过程。为了验证所提出方法的有效性，本文使用商用GaN HEMT器件CG2H40010F在1.3–1.8 GHz频段内设计并加工了一款负载调制增强的高效率DPA，并给出了可参考的设计过程。实验结果表明：在饱和状态下，放大器输出功率达43.7–44.5 dBm，漏极效率(drain efficiency, DE)超过69.1%；6 dB回退工作状态下，DE仍保持在62.9%–69.4%，增益为9.7–10.5 dB；9 dB回退下，DE高达49.5%–57%，增益为10.3–11.5 dB。本文提出的等效跨导补偿理论通过补偿电流注入机制有效解决了传统DPA的负载调制瓶颈，为高效率的宽带DPA设计提供了新思路。
- Doherty功率放大器 /
- 有源负载调制 /
- 补偿支路 /
- 高效率
Abstract: Objective The modern wireless communication system imposes stringent requirements on the efficient dynamic range performance of RF power amplifiers. The Doherty Power Amplifier (DPA), leveraging the dynamic load modulation mechanism of the main and auxiliary amplifiers, achieves a breakthrough in efficiency at the power backoff point. This architecture has become the preferred solution for multi-carrier scenarios in 4G/5G macro base stations. Current research on DPAs primarily focuses on improving backoff efficiency, backoff range, and operating bandwidth. However, the DPA architecture has inherent drawbacks: the auxiliary amplifier, biased in Class C, has a weak current output capability compared to the main amplifier biased in Class AB, due to its low conduction characteristics and short turn-on time. This nonlinear imbalance leads to a degradation in amplifier performance. Methods This paper addresses the issue of insufficient load modulation caused by the weak current output capability of the auxiliary amplifier. An equivalent transconductance compensation theory is proposed, which compensates for the current output capability of the auxiliary amplifier under Class C bias by injecting a compensatory current into the branch. This results in the development of a load-modulation-enhanced quasi-ideal high-performance DPA, fundamentally solving the inherent issue of weak output current in the auxiliary amplifier of traditional DPA structures. Results and Discussions In this paper, a load-modulation-enhanced DPA was designed and fabricated using the commercially available GaN HEMT device CG2H40010F in the 1.3–1.8 GHz frequency band. Experimental results show that, under saturation, the amplifier output power ranges from 43.7 to 44.5 dBm, with a drain efficiency (DE) exceeding 69.1%. At a 6 dB backoff, the DE remains between 62.9% and 69.4%, with a gain ranging from 9.7 to 10.5 dB. At a 9 dB backoff, the DE reaches as high as 49.5% to 57%, with a gain ranging from 10.3 to 11.5 dB. The equivalent transconductance compensation theory proposed in this paper effectively addresses the load modulation bottleneck of traditional DPAs through the current injection mechanism. This provides new insights for the design of broadband RF power amplifiers with high power backoff efficiency. Conclusions This paper introduces the concept of equivalent transconductance compensation by incorporating a third compensation branch into the traditional DPA structure. This compensation mechanism corrects the weak output current of the auxiliary amplifier caused by Class C bias and its short turn-on time, thereby achieving a quasi-ideal high-performance load-modulation-enhanced DPA architecture. To validate the proposed design method, a novel load-modulation-enhanced quasi-ideal DPA operating in the 1.3 GHz to 1.8 GHz frequency range was designed. The test results show that the proposed novel DPA achieves a saturated drain efficiency greater than 69.1%, with the drain efficiency at a 6 dB backoff ranging from 62.9% to 69.4%. At a 9 dB backoff, the drain efficiency reaches between 49.5% and 57%. Meanwhile, the linearized Adjacent Channel Leakage Ratio (ACLR) is measured to be lower than –49 dBc. These results effectively verify the feasibility of the design method, which is at the forefront of current research and demonstrates promising application prospects.
- Doherty power amplifier /
- active load modulation /
- compensation branch /
- high efficiency

HTML全文

图 1 (a) 传统 DPA 等效结构 (b)提出的等效跨导矫正的 DPA 结构

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图 2 理想和实际情况下主功放和辅功放的 (a) 电流以及相应的 (b) 负载变化对比

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图 3 不同情况下输出电流的随输出功率的变化图

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图 4 ：采用 CGH40025F 设计辅功放的输出电流随输入功率变化

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图 5 主功放电流源面处饱和以及功率回退情况下的阻抗

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图 6 电路设计具体参数

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图 7 设计加工的 DPA 的照片

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图 8 测试的 DPA 的漏极效率和增益与输出功率的关系

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图 9 测试的 DPA 的漏极效率和增益与频率的关系

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图 10 实验室的线性化验证平台

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图 11 1.5 GHz下宽带信号的测试和线性化验证结果

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表 1 同近几年发表的DPA 的性能对比

文献	频率 (GHz)	饱和输出(dBm)	饱和 DE(%)	回退 DE(%)
[14]	1.6–2.7	43.8–45.2	56–75.3	46.5–62.5
[6]	1.5–2.55	42.6–44.4	50.7–69.7	43.43–57
[15]	3.1–3.6	41.8–42.8	49.6–53.4	35.4–41.1
[16]	0.7–1.1	42.6–43.3	66–74.6	57.0–61.5
本文	1.3–1.8	43.7–44.5	68.8–71.9	62.9–69.4

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参考文献(16)

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