为获得更高的数据吞吐率和支持多个应用场景，5G通信系统需要具备宽频带工作能力。同时，为提升单位频谱利用效率，还将采用具有超高峰均比值的复杂调制信号。这些信号特征为功率放大器的设计带来了巨大的技术挑战。对此，本项目将重点研究Doherty和outphasing两种最具代表性的高效率负载调制型功率放大器的工作带宽和回退范围提升技术。首先，分析研究两种结构常规负载调制网络的带宽限制机理，通过引入宽带匹配网络综合、谐波修正与控制、无色散传输线等措施，分别克服各自的工作带宽不足问题。在此基础上，研究探索针对多路Doherty结构的多目标协同优化方法以及Doherty和outphasing架构融合方案，在保持大工作带宽和高效率的同时进一步提升放大器回退范围，并且完善相关设计理论。本项目的实施将解决目前5G通信用功率放大器面临的一些主要技术难题，具有重要的科学和应用价值。

To increase data throughput and support multiple application scenarios, 5G communication system is required to have wide-band operation capability. Besides, to improve spectrum efficiency, complex modulated signals with high peak-to-average power ratio (PAPR) will also be adopted. These characteristics bring in great challenges for power amplifier designs. In this context, this project investigates the bandwidth and back-off range enhancement technology of Doherty and outphasing power amplifiers, the most representative load modulated amplifier types. Firstly, the bandwidth limiting mechanisms of these two structures will be studied. Next, the bandwidth shortage of both designs is overcome, respectively, by introducing innovative techniques such as wide-band matching network synthesis, harmonic manipulation, non-dispersion transmission line and so on. On the basis of these efforts, design strategies for muti-objective synergistic optimization matching for multi-stage Doherty amplifier and integrated Doherty-outphasing configuration will be explored to improve the back-off range while maintaining the operating bandwidth and efficiency. The implementation of this work is supposed to solve some critical technical problems faced by the power amplifier for 5G communication at present, which has great scientific and application values.