X波段涡旋波束传输特性的研究

发布时间：2018-06-12 03:49

本文选题：轨道角动量 + 大气湍流　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：近年来,如何进一步提高信道容量以满足人们日益增长的信息需求成为了通信领域的研究热点。轨道角动量(Orbital Angular Momentum)理论上具有无限多个模式,而且模式间彼此正交,因此携带轨道角动量的电磁波束为拓展信道容量提供了潜在的理论方法,形成了继时分复用,频分复用,波分复用等复用方式之后的一种全新的复用方式——态分复用。在通信及雷达探测等领域具有广泛的应用前景。首先,本文基于拉塞尔-高斯波束的解析表达式,研究了涡旋电磁波的产生,对相位奇点和轨道角动量特性进行了详细分析。利用Matlab仿真软件计算了涡旋波束在理想环境下,不同模式数相同截面条件下的能量和相位分布,相同模式数不同截面条件下的能量和相位分布及混合模式条件下的能量和相位分布。其次,介绍了Kolmogorov大气湍流理论,标量场衍射理论和角动量谱分解理论,进而针对微波波段上对大气折射率常数造成主要影响的各因素,建立模型并对大气折射率数值的变化进行了分析,在此基础上采用功率谱反演法和Zernike多项式法分别构造相位屏,比较了二者的优缺点并以此为基础模拟涡旋波束在湍流环境中传播特定距离时大气湍流对轨道角动量模式能量及相位分布的影响,计算并分析了涡旋电磁波传输特定距离后的轨道角动量能量占比分布情况。最后,确定了本文对于波前畸变程度的评价标准——RMS(Root Mean Square)和PV(Peak to Valley)。介绍了S-H波前探测器的系统组成,基于模式法波前重构理论对采用Zernike多项式进行波前重构过程中存在的截断误差进行了仿真分析。对经过湍流后的畸变波前进行了补偿,并通过谱分解方法对轨道角动量模式补偿效果进行了分析。
[Abstract]:In recent years, how to further improve the channel capacity to meet the increasing information needs has become a research hotspot in the field of communication. Orbital angular momentum (Orbital Angular momentum) has infinite modes in theory, and the modes are orthogonal to each other. Therefore, the electromagnetic beam carrying orbital angular momentum provides a potential theoretical method for expanding the channel capacity and forms the following time division multiplexing (TDM) and frequency division multiplexing (FDM). After wavelength division multiplexing and other multiplexing, a new multiplexing mode-state division multiplexing. It has a wide application prospect in the field of communication and radar detection. Firstly, based on the analytical expression of Laser-Gaussian beam, the generation of vortex electromagnetic wave is studied, and the characteristics of phase singularity and orbital angular momentum are analyzed in detail. The energy and phase distributions of vortex beam in ideal environment with the same cross section of different modes are calculated by Matlab simulation software. The distribution of energy and phase under the same number of modes and different cross sections and the distribution of energy and phase under mixed mode. Secondly, Kolmogorov's atmospheric turbulence theory, scalar field diffraction theory and angular momentum spectrum decomposition theory are introduced. The model is established and the variation of atmospheric refractive index is analyzed. Based on this, the phase screen is constructed by power spectrum inversion method and Zernike polynomial method, respectively. The advantages and disadvantages of the two methods are compared and the effects of atmospheric turbulence on the energy and phase distribution of orbital angular momentum model are simulated when vortex beam propagates at a specific distance in turbulent environment. The distribution of orbital angular momentum energy after the vortex electromagnetic wave propagates at a specific distance is calculated and analyzed. Finally, the criteria for evaluating the degree of pre-distortion of Yu Bo are determined, which are the RMS Root mean Square-and the Peak to Valleyn. The system composition of S-H wavefront detector is introduced. The truncation error in the process of wavefront reconstruction using Zernike polynomials is simulated and analyzed based on the mode method wave-front reconstruction theory. The distortion wavefront after turbulence is compensated and the compensation effect of orbital angular momentum mode is analyzed by spectral decomposition method.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN011

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