动态有源负载优化与瞬时包络幅度分段的宽带高效率发射机研究

It will be studied with time-domain analysis methods in this project, including the bandwidth extension effects of the active load modulation and the average efficiency improvement method of real-time division of amplitude envelopes. The theoretical performance will be evaluated, and the practice of the two methods in power amplifier designs will be proposed. Reconfigurable multi-path transmitter architecture will be explored to cover the whole operation bandwidth of a transistor. And the time-domain analysis of dynamics and optimization methods will be developed to apply for this architecture. Ultra-wideband reconfigurability and adaptation to high efficiency amplification with high-order modulated signals are the two most important merits of the transmitter, and these merits will be verified by theories and measurements. The major researches include that 1> Simplified performance analysis, evaluation models and optimizations in time-domain for the broadband reconfigurable multi-path transmitter, 2> Broadband high efficiency power amplifiers with active load modulation, 3> The theories and implementation of distributed active load modulation, 4> Dynamic reconfigurable transmitter architecture which can cover the whole operation bandwidth of a RF power transistor, 5> The theory of real-time division of amplitude envelopes, the multi-path transmitter which can improve the transmitter’s average efficiency and the low loss path selection broadband circuits.

本项目将运用时域分析等方法对有源负载调制的带宽扩展理论、瞬时包络幅度分段提高平均效率的方法进行研究，评估其理想性能，提出它们在功率放大器中的实现方法；探索可覆盖晶体管工作带宽的可配置多支路发射机结构，发展应用于该结构的时域动态分析和优化方法；从理论和实践上证明该结构具有超宽带可重配置能力、能适应高阶调制信号的高效率放大。主要研究内容包括：①简化的时域性能分析、评价模型与优化方法；②引入有源负载调制技术的宽带高效率功率放大器；③分布式有源负载调制原理与方案；④覆盖功率晶体管工作频段的动态可重配置发射机结构；⑤瞬时包络幅度分段原理，提升发射机平均效率的多支路功率放大器结构及宽带低损耗支路切换电路。

为了解决提高射频发射机的宽带、高效率性能指标的电路结构与设计方法问题，本项目基于有源负载调制理论与瞬时包络幅度分段方法，开展的主要研究内容包括：①瞬时包络幅度分段放大原理及基本性能、切换结构研究；②有源负载调制基本原理及阻抗调制范围研究；③支持时域仿真与复杂优化的联合仿真平台研究；④采用无源匹配网络的超宽带高效率功放设计方法；⑤Doherty有源负载调制功率放大器的改进设计方法；⑥高效率功放的数字预失真技术；⑦分布式高效率放大器结构等。采用模式插值的理论，突破了当前无源匹配网络宽带功率放大器的设计带宽极限；采用有源负载调制理论，实现了1-4GHz的跨多倍频程高效率功放设计；采用不同的高效率功放类型、引入实部与虚部阻抗组合、采用开关可重配置网络等方法，拓展了Doherty功放的设计带宽与回退量；结合瞬时包络幅度的方法与超宽带功放的设计成果，完成了高效率宽带发射机的理论验证，可以实现超过500MHz的宽带信号的实时放大，工作射频频带可跨越1-4GHz，理论上可以超越当前Doherty功放的性能。在项目执行期间，共发表SCI检索论文25篇，其中中科院二区以上论文9篇，JCR一区论文18篇，被引79次，项目产生的理论成果得到广泛关注，并与企业界衍生了多项科研合作项目；发表国际会议论文7篇；申请国家发明专利7项；培养已毕业博士生6名，硕士生6名；获得IMS'2018国际功放竞赛第一名。