平面螺旋轨道角动量电磁波及其应用研究

发布时间：2018-05-24 16:04

  本文选题：平面螺旋轨道角动量电磁波 + 射频涡旋波束　； 参考：《浙江大学》2017年硕士论文

【摘要】：无线通信和人类的生活息息相关。随着智能终端的普及和移动互联网的飞速发展,人们对数据传输速率的需求呈指数级不断提升,如何进一步提高通信容量一直是无线通信领域迫切需要解决的问题。轨道角动量(OAM)作为电磁波的一项基本属性,近年来引起了众多学者的广泛关注。由于携带不同轨道角动量的电磁波之间是完全正交的,轨道角动量可以作为一个新的维度来携载信息,并具有提升通信系统容量的潜力。在射频领域,由于携带轨道角动量的涡旋电磁波具有不可避免的波束发散性和中心相位奇点问题,在实际通信系统中对其接收和解调提出了巨大的挑战。在接收端天线口径有限的情况下,不同态的涡旋电磁波之间的正交性会被破坏,通信容量并得不到提高。本文从电磁波的轨道角动量的物理原理出发,分析了射频轨道角动量电磁波的发展和研究现状,针对其特有的发散和相位奇点问题,提出了一种新型的涡旋波束,即平面螺旋轨道角动量电磁波(PSOAM)。这种波束沿平面传播,不同态波束的发散角一致,可有效避免相位奇点问题。本文对平面螺旋轨道角动量电磁波的产生方式、传播特性和潜在应用进行了详尽的研究和细致的阐述。本文首先提出了产生平面螺旋轨道角动量电磁波的三种天线的理论模型:环形行波天线、同轴谐振腔天线和回音壁模式介质谐振腔天线,天线的仿真和实验结果也验证了产生的波束不仅保持了涡旋波束的特性而且是沿平面传播的。在阐述了平面螺旋轨道角动量电磁波的相关机理和优势之后,本文提出了 一系列基于这种电磁波的潜在应用,分析了相关应用的理论模型并进行了实验验证。第一,将平面螺旋轨道角动量电磁波和现有的多输入多输出通信系统(MIMO)相结合,提出了一种新型的基于平面涡旋波束的多入多出系统(PSOAM-MIMO),首次了证明利用了射频轨道角动量波束的无线通信系统可以提升通信系统容量。我们对这个系统在直射信道和非直射信道下的系统性能分别进行了详细的分析,进行了相关实验,实验结果与理论分析吻合,验证了模型的正确性和系统的可行性。第二,将多个不同态的平面螺旋轨道角动量电磁波组合进行波束赋形(PSOAM-BF)。相比于传统的相控阵波束赋形的方法,利用平面螺旋轨道角动量电磁波进行波束赋形具有馈电网络简单、扫描时波束形状固定、合成的波束仍具有正交性、有希望继续增加频谱效率等优势;本文详细研究了影响波束形状的相关参数并进行了实验验证。平面螺旋轨道角动量电磁波作射频轨道角动量波束的一种,具有实现简单、各态方向性一致、链路估计一致等优势,能够和现有的多入多出系统相结合,实现更好的系统性能,在未来的无线通信网络和雷达系统中有着广泛的应用。
[Abstract]:Wireless communication is closely related to human life. With the popularity of intelligent terminals and the rapid development of mobile Internet, the demand for data transmission rate is increasing exponentially. How to further improve the communication capacity has been an urgent problem in wireless communication field. Orbital angular momentum (OAM), as a basic attribute of electromagnetic waves, has attracted extensive attention of many scholars in recent years. Because the electromagnetic waves carrying different orbital angular momentum are completely orthogonal, orbital angular momentum can be used as a new dimension to carry information and has the potential to enhance the capacity of communication systems. In the RF field, due to the inevitable beam divergence and the singularity of the central phase of the vortex electromagnetic wave with orbital angular momentum, it is a great challenge to receive and demodulate it in practical communication systems. Under the limited aperture of the antenna at the receiving end, the orthogonality of vortex electromagnetic waves in different states will be destroyed, and the communication capacity will not be improved. In this paper, based on the physical principle of orbital angular momentum of electromagnetic wave, the development and research status of RF orbital angular momentum electromagnetic wave are analyzed, and a new type of vortex beam is proposed for its peculiar divergence and phase singularity. That is the planar spiral orbit angular momentum electromagnetic wave PSOAM. This kind of beam propagates along the plane, and the divergence angle of different states is the same, which can effectively avoid the phase singularity problem. In this paper, the generation mode, propagation characteristics and potential applications of planar helical orbital angular momentum electromagnetic wave are discussed in detail. In this paper, the theoretical models of three kinds of antennas producing planar helical orbit angular momentum electromagnetic waves are proposed: the annular traveling wave antenna, the coaxial resonator antenna and the echo-mode dielectric resonator antenna. The simulation and experimental results of the antenna show that the generated beam not only keeps the characteristics of the vortex beam but also propagates along the plane. After explaining the relative mechanism and advantages of planar helical orbit angular momentum electromagnetic wave, a series of potential applications based on this kind of electromagnetic wave are proposed, and the theoretical model of the related application is analyzed and verified by experiments. First, the planar helical orbit angular momentum electromagnetic wave is combined with the existing multi-input multi-output communication system (MIMOO). A new multi-input multi-output system (PSOAM-MIMOA) based on planar vortex beam is proposed. It is proved for the first time that the radio communication system using the RF orbit angular momentum beam can enhance the capacity of the communication system. The performance of the system in direct channel and non-direct channel is analyzed in detail, and the experimental results are consistent with the theoretical analysis, which verifies the correctness of the model and the feasibility of the system. Secondly, several planar helical orbital angular momentum electromagnetic waves with different states are combined to form a beamforming PSOAM-BFF. Compared with the traditional beamforming method of phased array, the beamforming using planar helical orbit angular momentum electromagnetic wave has the advantages of simple feed network, fixed beam shape during scanning and orthogonality of the synthesized beam. It is hopeful to continue to increase the spectral efficiency. The related parameters affecting the shape of the beam are studied in detail and verified by experiments. The planar helical orbit angular momentum electromagnetic wave is a kind of radio frequency orbit angular momentum beam. It has the advantages of simple realization, uniform orientation of all states, consistent link estimation, and so on. It can be combined with the existing multi-input multi-output system to achieve better system performance. It is widely used in future wireless communication networks and radar systems.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN92;O441.4
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本文编号：1929702