无线轨道角动量通信与雷达目标成像技术研究

发布时间：2018-04-15 12:23

本文选题：无线通信 + 轨道角动量　；参考：《浙江大学》2017年硕士论文

【摘要】：随着无线通信技术的快速发展,无线频段的频谱拥塞问题愈发严重,因此,在频谱资源有限的情况下研究能够提高频谱利用效率的新型无线通信技术具有重要意义。研究表明,轨道角动量作为电磁场所携带的基本物理量之一,理论上拥有无穷多种本征模式,且不同本征模式之间具有正交性,如果能够将轨道角动量的这一特性应用于无线通信中,则有可能大幅提高现有无线通信的信道容量。本文以此为基础,对轨道角动量在未来无线通信中应用的可行性、技术思路和方法进行相关研究,包括如何在射频段生成携带轨道角动量的涡旋波束,涡旋波束的传播特性分析,以及轨道角动量模式的检测等问题;同时,本文基于涡旋波束所具有的独特的空间相位特性,研究了将轨道角动量应用于雷达目标检测的可行性,相关研究内容概括如下。本文提出了一种用于在射频段生成涡旋波束的环形偶极子天线阵列。针对在实际的应用场景中涡旋波束的生成问题,本文以天线设计领域中经典的偶极子天线作为均匀环形天线阵列的阵元,对于偶极子在环形阵列中的四种排布方式,通过仿真分析发现只有平行偶极子环形阵列在线性相位激励下才能生成携带轨道角动量的涡旋波束,在此基础上,详细研究了在该偶极子排布方式下环形阵列的各个参数对涡旋波束辐射特性的影响。同时基于环形天线阵列作为涡旋波束的接收端,仿真验证了在该涡旋波束接收配置下轨道角动量模式间的正交性以及利用轨道角动量增加无线通信信道容量的可行性。本文提出了一种涡旋波束轨道角动量模式的偏轴检测方法。针对传统基于两天线的相位梯度检测法在检测阵列相对于波束轴存在横向偏移时检测结果不再可靠的问题,提出一种基于均匀环形天线阵列的不需要确知波束轴位置即可检测轨道角动量模式的检测方法,仿真结果表明当检测阵列相对于波束轴的横向偏移量在给定范围内时,均可得到可靠的模式检测结果,且检测性能不受偏移量大小的影响。在此基础上,针对波束轴偏移量更大的情形,本文又提出两种适合低阶轨道角动量模式偏轴检测的网格天线阵列结构,相对于均匀环形阵列,这种网格阵列具有更大的空间覆盖区域,且只要波束轴落入该阵列的覆盖区域内,就能检测出其轨道角动量模式,并能同时确定该波束轴所在的网格区域,这为后续收发阵列偏移校正等轨道角动量通信信号处理技术提供了有价值的参考。本文最后提出了一种基于涡旋电磁波的雷达目标二维成像方法。基于由均匀环形天线阵列生成的涡旋电磁波投射下理想散射点的两种回波模型,对雷达目标回波信号进行轨道角动量模式采样并计算相关函数,运用多重信号分类(MUSIC)算法得到空间谱函数并进行二维谱峰搜索从而实现对雷达目标俯仰角和方位角的二维联合检测,与现有的基于涡旋电磁波只能进行目标方位角成像的雷达成像方法相比,本方法能够同时实现目标方位角和俯仰角的二维联合成像,同时相对于传统平面电磁波经典的MUSIC二维成像算法,本方法能够实现更高的角度成像分辨率,且本方法在探测目标的过程中雷达不需要相对运动以及波束扫描,这对现代新型雷达系统的设计具有重要意义。
[Abstract]:With the rapid development of wireless communication technology, wireless frequency spectrum congestion problem is increasingly serious, therefore, research has important significance in improving the new wireless communication technology, the spectrum utilization efficiency in the case of limited spectrum resources. Studies show that one of the basic physics of orbital angular momentum as the electric magnetic field that carries the theory with an infinite number of the sign pattern has orthogonality between different intrinsic mode and, if the orbital angular momentum of the characteristics used in wireless communication, is likely to significantly improve the existing wireless communication channel capacity. Based on the orbital angular momentum in the feasibility of the application of wireless communication in the future, technology ideas and methods. The related research, including how to generate vortex beam with orbital angular momentum in the radio frequency range, the propagation characteristics of vortex beam, and the orbital angular momentum model The problem of detection; at the same time, the unique characteristics of the phase space is based on the vortex beam, the feasibility of the orbital angular momentum is applied in radar target detection, the related research contents are summarized as follows. This paper presents a circular dipole antenna array to generate vortex beam in the RF section for generating problem. Aiming at the vortex in the application the scene in the actual beam, based on the classical dipole antenna antenna design in the field as a uniform circular antenna array element, the four in the annular array arrangement of dipoles, the simulation results show that the vortex beam only parallel dipole circular array in linear phase excitation to generate carrying orbital angular momentum, on the basis of on the influence of radiation characteristic of vortex beam in various parameters of the dipole arrangement under the ring array are studied in detail. At the same time Circular antenna array based on vortex beam as the receiving end, simulation and verification of orthogonality in the vortex beam receiving configuration under orbital angular momentum between the modes and the feasibility of using orbital angular momentum to increase the channel capacity of wireless communication. This paper proposes a detection method of off-axis vortex beam orbital angular momentum mode. The traditional phase gradient detection the two method based on antenna array detection in detection results are no longer reliable with respect to the axis of the beam transverse offset problem, proposes a uniform circular antenna array does not need to know the position based on the axis of the beam can be detected orbital angular momentum model, the simulation results show that when the transverse offset detection array relative to the axis of the beam in a given range, can be model reliable test results, and the detection performance is not affected by the offset size. On this basis, according to the The axis of the beam offset is greater, this paper puts forward two kinds of grid antenna array structure for low order modes of the orbital angular momentum of off-axis detection, compared with the uniform circular array, the grid array has greater spatial coverage area, and as long as the axis of the beam into the array covering area, can detect the track the angular momentum model, and can also determine the grid area where the axis of the beam, which provides valuable reference for the subsequent receiving array offset correction of orbital angular momentum of communication signal processing technology. This paper finally puts forward a 2-D radar target imaging method based on electromagnetic vortex wave. Two echo model of ideal scattering points the electromagnetic wave generated vortex projection ring antenna array is composed of uniform based on radar echo signal of orbital angular momentum mode sampling and calculating the correlation function, the use of multiple signal classification (MUSIC) algorithm to obtain the spatial spectrum function and spectral peak searching so as to realize two-dimensional combined detection of radar target azimuth and pitching angle, compared with the existing radar imaging method of target azimuth imaging of vortex electromagnetic wave only based on this method can achieve planar imaging target azimuth and elevation angle. At the same time compared to the traditional algorithm of MUSIC imaging of plane electromagnetic wave classic, this method can achieve higher angle resolution, and this method in target detection in radar without relative motion and beam scanning, which is of important significance for modern radar system design.

【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】：TN957.52;TN92

【参考文献】