摘要：涡旋电磁波是具有螺旋状相位波前的特殊电磁波。通过发射涡旋电磁波对目标进行雷达探测时，由于涡旋电磁波束独特的相位分布使得其具有不同的轨道角动量态，不同轨道角动量态的电磁波对应于不同的雷达散射回波。此外，涡旋电磁波相当于平面波从多个角度照射目标，因而它在目标特性空间分集方面具有优势。本文主要研究以涡旋电磁波作为发射波，进行雷达回波分析以及目标成像来获取更多目标特性信息。

本文主要工作如下：首先研究涡旋电磁波的产生原理以及不同模式数的涡旋电磁波特性。在了解涡旋电磁波原理的基础上，利用矩量法(MoM)分析涡旋电磁波照射下的简单目标的电磁散射特性。最后研究基于涡旋电磁波的新型雷达目标成像方法，分析它相对于传统成像的优势。这些研究将为新体制的雷达探测系统设计提供理论依据。

关键词：涡旋电磁波轨道角动量(OAM)电磁散射特性矩量法(MoM)雷达目标成像

毕业设计说明书外文摘要

Title  New Radar Target Imaging Based On The Vortex Electromagnetic Wave             

Abstract：The vortex electromagnetic wave is a special electromagnetic wave which has a helical phase wave. When we detect a target by launching a vortex wave, due to the unique phase distribution of the vortex beam, it has different orbital angular momentum states. Electromagnetic waves with different orbital angular momentum correspond to different radar scattering echoes. In addition, the electromagnetic vortex is equivalent to a plane wave which irradiates objects from multiple angles. So relative to the plane wave, the electromagnetic vortex has an advantage in terms of spatial persity of target characteristics. In this paper, we focus on using vortex electromagnetic waves as the emission wave, and analyze radar echo and image the target to obtain more target characteristic information. 

The main work of this paper is as follows. Firstly, we learn the principle of vortex electromagnetic wave generation and the vortex electromagnetic wave characteristics of different modes. On this basis, the electromagnetic scattering of the vortex electromagnetic wave to the simple target is obtained by numerical simulation using the computational electromagnetism method. Finally, a new radar target imaging method based on vortex electromagnetic wave is studied. These studies will provide a theoretical basis for the design of the new radar detection system. 

Keywords ： vortex electromagnetic wave, orbital angular momentum (OAM), electromagnetic scattering characteristics, moment method (MoM), radar target imaging 

目次

1绪论.1

1.1研究的背景及意义1

1.2国内外发展历史与现状1

1.3本文的主要工作内容及结构安排2

2涡旋电磁波...3

2.1引言3

2.2涡旋电磁波原理..3

2.3相控阵天线产生的涡旋电磁波空间相位分布..7

2.4数值算例及仿真..8

2.5本章小结...10

3矩量法的基本原理和实现..11

3.1引言...11

3.2矩量法的基本原理...11

3.3金属体散射的电场积分方程和磁场积分方程.12

3.4求解过程...15

3.5数值算例及仿真.16

3.6本章小结...18

4基于涡旋电磁波的新型成像方法19

4.1引言...19

4.2传统成像方法...19

4.3基于涡旋电磁波的新型成像...21

4.4数值算例及仿真.24

4.5本章小结...27

结论28致谢29参考文献30

图2.1不同模式数的涡旋电磁波的电场强度和相位分布4图2.2螺旋抛物面天线6图2.3改变介质板的厚度6图2.4相阵控天线7图2.5阵列直径与中心张角及辐射增益的关系8