基于CSO算法的阵列天线旁瓣电平抑制方法研究

发布时间：2018-03-15 12:09

本文选题：LAA　切入点：CAA　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：阵列天线作为无线通信过程中最重要的部分,随着社会信息交流需求的急剧增加,正面临着越来越大的挑战。与此同时,巨大的通信需求与十分有限的频谱资源之间的矛盾也日益增加,如何高效地利用频谱资源、如何在保证通信质量的前提下大规模地提高系统吞吐量成为了科研人员亟待解决的重要课题。为了更好的研究这一课题,产生了以阵列天线方向图综合为核心技术的智能天线技术,这种技术能够有效的提高频谱利用率,并且减少通信过程中的能量逸散。智能天线技术采用智能的方式配置天线阵列的参数,通过电磁波的叠加和干涉产生空间定向波束,并将天线信号有目的性的导向具体方向,即将天线主波束对准用户信号到达方向,将旁瓣或者零陷对准干扰信号到达的方向,从而充分利用有用信号和抑制干扰信号,并减少能量在非目标方向上的逸散。阵列天线是一种多天线(辐射器)的结构,其中单独的天线或辐射器被称为单元,每个单元按照直线或者更复杂的形式排列组合在一起。阵列的构成通常由天线馈电电流、间距、长度等不同参数来定义,并利用电磁波的干涉和叠加原理产生具有某种特性的辐射信号,从而满足不同场合的应用需求。例如,相控阵雷达天线阵列需要低旁瓣和高分辨率,而普通的即时通信需要高增益。天线阵列中涉及到许多参数,他们都可以直接或者间接的影响辐射特性,如阵元的数目,阵元的位置,激励振幅,和激励相位。通过这些参数的设计和调整,天线阵列的波束方向图可以产生不同的辐射性能。因此,一组最佳的参数组合能够产生最优化的辐射方向图。本文首先以直线型和圆形天线阵列为模型,提出一种改进算法CSCSO,利用其优化模型中阵元间距与阵元激励振幅,在已知阵元数目的情况下,设计有旁瓣最大电平抑制效果的天线阵列,得到具有更高的主瓣方向性和更低的最大旁瓣水平的阵列天线方向图。同时,与Uniform、CSO、CS、PSO算法进行了仿真对比。结果表明,CSCSO有效降低了最大旁瓣电平并提高了主瓣方向性,具有更好的优化效果。接下来,本文针对随机分布的阵列天线模型,提出了一种改进的混合启发式群智能优化算法称为BCSO算法,在阵列中的节点位置不能被控制的情况下,优化阵列天线方向图的最大旁瓣电平。通过产生一组较优的激励电流值来优化辐射方向图。这种算法的性能与其他的群智能优化算法CSO、BBO、PSO和BAT仿真结果比较表明,提出的算法可以取得更好的波束辐射性能。
[Abstract]:As the most important part of wireless communication, array antenna is facing more and more challenges with the rapid increase of social information exchange demand. The contradiction between the huge communication demand and the very limited spectrum resource is also increasing day by day. How to make efficient use of the spectrum resource, How to improve the system throughput on a large scale under the premise of ensuring the communication quality has become an important task to be solved by researchers. The smart antenna technology based on array antenna pattern synthesis is produced, which can effectively improve the spectrum efficiency. Smart antenna technology uses smart way to configure the parameters of antenna array, generate spatial directional beam by superposition and interference of electromagnetic wave, and guide antenna signal to specific direction purposefully. That is, the main beam of the antenna is aimed at the direction of arrival of the user signal, and the sidelobe or zero trap is aligned to the direction of the interference signal, so as to make full use of the useful signal and suppress the interference signal. The array antenna is a multi-antenna (radiator) structure in which a single antenna or radiator is called a unit. Each element is arranged in a straight line or more complex form. The structure of the array is usually defined by different parameters such as antenna feed current, spacing, length, etc. The interference and superposition principle of electromagnetic wave is used to produce the radiation signal with certain characteristics, so as to meet the needs of different applications. For example, the phased array radar antenna array needs low sidelobe and high resolution. Common instant messaging requires high gain. Antenna arrays involve many parameters that directly or indirectly affect radiation characteristics, such as the number of elements, the location of the elements, and the amplitude of the excitation. Through the design and adjustment of these parameters, the beam pattern of the antenna array can produce different radiation performance. An optimal combination of parameters can produce an optimal radiation pattern. In this paper, a modified algorithm CSCSO is proposed, in which linear and circular antenna arrays are used as models, and the spacing of array elements and the amplitude of excitation are used to optimize the model. When the number of array elements is known, the antenna array with maximum sidelobe suppression effect is designed, and the antenna pattern with higher principal lobe directivity and lower maximum sidelobe level is obtained. The simulation results show that CSCSO can effectively reduce the maximum sidelobe level and improve the directional performance of the main lobe. In this paper, an improved hybrid heuristic swarm intelligent optimization algorithm called BCSO algorithm is proposed, which can not be controlled when the node position in the array cannot be controlled. The maximum sidelobe level of the array antenna pattern is optimized. The radiation pattern is optimized by generating a set of optimal excitation currents. The performance of this algorithm is compared with that of other swarm intelligence optimization algorithms, CSO-BBOPSO and BAT. The proposed algorithm can achieve better beam radiation performance.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP18;TN820.15

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