光控射频涡旋电磁波的发射技术研究

Orbital angular momentum (OAM) mode multiplexing in radio frequency (RF) proposes a new dimension of multiplexing way for wireless communication systems. It is one of the most promising methods for increasing the capacity of wireless communication systems, and also a frontier researching topic in the field of international optical communication systems. The flexible, accurate excitation, and the emission with the function of channel pretreatment, are the essential parts and the technical difficulties of votex mode, which need to be solved firstly. Currently, for the RF vortex, the research methods of the excitation and emission are far from mature. Therefore, this project focuses on the requirements and principal problems of the future OAM mode multiplexing wireless communication systems, and explores the excitation and emission technology of the RF votex mode. The project researches on “mechanism and mothods of flexible and accurate excitation of any radio frequency OAM mode based on microwave photons phase-shift technique”, “the mechanism and achievement methods of radio frequency OAM mode emission with the channel pretreatment function based on phased-antenna array”, and “the data signal modulation of radio frequency OAM mode”, respectively. Through the intensively research above, large bandwith, multi-mode, high efficiency, low crosstalk and low complexity methods of mode excitation and mode control are expected to be proposed. Furthermore, we will make innovation in “radio frequency vortex electromagnetic waves transmitter based on microwave photonics” by substantial theoretical research and experimental verification of this project. We believe that this project will contribute a lot to the development of OAM mode multiplexing communication systems in China, and provide valuable results for the next generation of ultra-high speed, ultra-high capacity wireless communication systems.

射频信号的轨道角动量（OAM）模式复用在通信系统中增加了新的复用维度，是提高无线信道容量的最有前景的方法之一，已成为当前国内外通信领域的前沿与热点研究问题。其中，灵活精准的电磁涡旋模式产生和信道预处理功能的模式发射是其首要解决的问题和难点技术。当前的涡旋波模式产生和发射方法还远不成熟。本课题面向未来OAM模式复用通信技术的需求和基本问题，探索射频涡旋电磁波的发射技术，对基于微波光子移相的任意射频OAM模式发射激励机理与方法、基于环形相控天线阵的射频OAM模式信道预处理发射机制、数据信号调制编码方式等三个方面进行研究，提出大带宽、多模式、低串扰、低复杂度的射频涡旋模式产生和控制方法，通过理论研究和实验验证，在“基于光控微波光子学的射频涡旋电磁波发射技术”方面形成创新。课题研究成果将为我国轨道角动量复用通信技术的发展提供有力支撑，并为向下一代超高速率、超大容量无线通信系统的演进提供重要参考。

项目组面向未来轨道角动量的复用通信需求，基于环形相控阵天线技术及微波光子相移阵列技术研究光控射频涡旋电磁波(RF-OAM)及光控射频涡旋波扫描发射、传输、编码三个方面展开深入研究。其一，在“基于微波光子移相的任意RF-OAM模式的发射激励机理与方法”方面提出对任意长度光纤具有色散免疫效果的相位控制方案，在微波光子相移领域，成功解决链路色散和带宽的矛盾，进而成功解决了大带宽、超大范围、精确的光子移相阵列，最终实现RF-OAM多模式发射及二维空间扫描。其二，在“基于射频OAM模式信道预处理传输机制”方面，利用环形相位梯度法及相位空间积分数学特征分析，实现任意双模式RF-OAM自动识别；通过微多普勒效应及相位时间累计方法，实现RF-OAM微小频移信号的测量；通过基于强度掩膜版的信道预处理和叠加态耦合传输结合的方式，提高射频涡旋波传输距离。其三，研究RF-OAM模式数据信号的调制编码方式，实现涡旋波加载信号传输。依托北京邮电大学信息光学与光通信国家重点实验室搭建了光控多功能射频涡旋波束通信探测实验平台。通过理论研究和实验验证，为轨道角动量复用无线通信系统的快速发展提供重要支撑。. 该项目发表科技论文共计36篇，其中SCI检索论文22篇，EI检索论文14篇。在Optics Letters，Optics Express等中科院JCR分区2区期刊发表论文共12篇，其中1篇于2019年10月被评为ESI高被引论文。18人次在OFC、CLEO，ECOC，ACP等光通信领域的国际一流学术会议上报告项目的最新研究成果，其中，Post-deadline报告1人次，ACP2017、ICOCN2017、OGC2019会议邀请报告3人次。参与国际学术会议并为分会场主席（TPC co-chair CLEO-PR2018, Session Chair CECNet2019）2人次；申请相关国家发明专利5项，已授权2项。提交国家标准1篇，已正式发布，并参与制定IEEE802.11aj国际标准；1人次获得2019年中国产学研合作军民融合个人奖。培养博士研究生9人，其中4人已毕业。.项目组超额完成了既定的预期目标。