微波无线能量传输中的集成滤波整流天线技术研究

Microwave Power Transmission (MPT) and Microwave Power Harvesting can get rid of the restrictions of cables in traditional power transmission and meet the requirements of various applications. Rectenna is a key device for microwave power collecting and RF-DC converting in MPT system. In traditional rectenna design, the filters and impedance match networks would introduce additional loss, and the common microstrip antenna element often behaves in relatively narrow band characteristic. The performances of rectenna such as efficiency, integration and broadband properties need to be improved. Based on the concept and theory of integrated filtering antenna and the rectifying circuit theory, this project will conduct the research of integrated filtering rectenna. Considering the antenna radiator as the last resonator of the filter, the research on modeling and analysis of integrated filtering antenna will be carried out to propose novel highly integrated antennas and array which exhibit multiple functions such as radiation, filtering, complex impedance match, power dividing and combining or duplexing, simultaneously. Then combined with the method of integrated filters as class-F loads in rectifying circuit, the design of circular polarized integrated filtering rectenna will be investigated to realize high efficiency broadband rectenna with high harmonic suppression. Finally, the research of dual-band compound antenna array for pilot signal transmitting and microwave power rectifying will be carried out based on the integrated filtering antenna’s functions of filtering, power dividing/combining and duplexing. The research outputs in this project are expected to resolve the technological difficulties in high efficiency integrated rectenna design and provide technical foundations for MPT system efficiency improvements.

微波无线能量传输与电磁能量获取摆脱了传统能量传输的电缆限制，可以满足多个领域的应用需求，整流天线是完成电磁能量收集和微波-直流能量转换的重要装置。目前常规整流天线中存在的滤波器、阻抗匹配网络等损耗及常规微带天线的窄带特性，使得其效率及带宽等特性存在可提升的空间。本项目基于集成滤波天线的概念和理论将其与整流电路相结合，开展集成滤波整流天线技术研究：将天线单元作为滤波器电路理论中的谐振单元开展集成滤波天线建模和分析理论研究，提出具有辐射、滤波、复数阻抗匹配、功分/功合、双工等功能的天线及阵列结构；结合在整流电路中利用集成滤波器实现F类负载，研究高效宽带圆极化集成滤波整流天线设计方法；基于集成滤波天线的滤波、功分/功合及双工功能，研究高隔离度导引信号发射与微波能量接收整流复合双频天线设计。本项目研究有望突破整流天线高效集成的技术难点，为微波无线能量传输效率提升提供技术基础。

微波无线能量传输与电磁能量获取摆脱了传统能量传输的电缆限制，可以满足多个领域的应用需求，整流天线是完成电磁能量收集和微波-直流能量转换的重要装置。目前常规整流天线中存在的滤波器、阻抗匹配网络等损耗及常规微带天线的窄带特性，使得其效率及带宽等特性存在可提升的空间。本项目基于集成滤波天线的概念和理论将其与整流电路相结合，开展集成滤波整流天线技术研究：将天线单元作为滤波器电路理论中的谐振单元开展集成滤波天线建模和分析理论研究，提出具有辐射、滤波、复数阻抗匹配、功分/功合、双工等功能的天线及阵列结构；首次提出将滤波天线的概念与整流电路相结合，开展滤波整流天线技术研究：将天线单元作为滤波器电路理论中的谐振单元开展复数阻抗匹配滤波天线建模和分析研究，提出具有辐射、滤波、复数阻抗匹配等功能的天线结构。设计了C频段基于1/8模SIW（EMSIW）谐振器的复数阻抗匹配滤波天线，通过复数阻抗匹配省去了整流电路的阻抗匹配网络，采用EMSIW谐振器来增加天线增益，并通过结构设计改善了前后比以提高效率。测试结果表明所提出的天线阻抗带宽在C频段超过14.5％，增益高于8dBi，轴比带宽超过8.5％，前后比超过18dB，与特定整流电路在5.8GHz共轭匹配，具有良好的带外抑制特性，可抑制二次谐波再辐射。结合在整流电路中利用集成滤波器实现F类负载提出了一种宽频整流电路。采用单管并联整流结构，通过在输出端接微带滤波器，实现F类整流电路工作模式，在5-7GHz频带内整流效率高于60%。基于集成滤波天线的滤波、功分/功合及双工功能，研究高隔离度导引信号发射与微波能量接收整流复合双频天线设计，提出了一种宽带高隔离度低剖面的双端口圆极化天线。天线在4.7-7.5GHz频带内工作在左旋圆极化模式，反射系数低于-10dB，轴比优于3dB，左旋圆极化增益保持在10dBi左右；在2.45GHz频段内为右旋圆极化模式，辐射效率高于85%，最高91%，高低频隔离度优于-44dB。本项目突破了整流天线高效集成的技术难点，可为微波无线能量传输效率提升提供技术基础和技术途径。