四维天线阵的高效优化及空间谱估计技术研究

发布时间：2018-05-18 22:40

本文选题：四维天线阵 + 时间调制　；参考：《电子科技大学》2014年硕士论文

【摘要】：随着无线电子系统的快速发展,阵列天线对于无线系统整体性能的提升起着越来越重要的作用。广泛应用于各种电磁环境中的阵列天线往往要求其具有低副瓣、多波束、波束扫描以及波束赋形等特性,这些性能要求极大的增加了阵列天线的设计难度和馈电网络的复杂程度,并且要求器件具有较高精度。引入时间设计自由度的四维天线阵能够有效地降低天线阵列设计的难度和对馈电幅度、相位等的依赖。此外,其优越于常规阵列天线的辐射特性也越来越多地得以发掘并受到广泛关注。本文基于四维天线阵的频域特性,对四维天线阵的高效设计和系统应用基础两方面展开深入研究。针对这两方面的研究主要涵盖了以下内容:在四维天线阵的高效设计方面,针对四维天线阵开关时序优化设计中的效率问题,提出了逐位进化遗传算法。考虑周期性时间调制的特点,将开关时序的数学表达与物理含义进行有机结合。算法将染色体中的每一个基因作为独立进化单元,并引入基因保留概率的概念,通过保留优质基因,反转劣质基因的方法实现了利用种群中的所有个体共同推进基因进化。通过与物理含义的结合,算法显著提高了迭代的方向性,且针对含有大量参数的大阵列设计,较现有算法具有更好的优化能力。大量的仿真实验表明,将逐位进化遗传算法用于四维天线阵的优化设计,不仅能获得更好辐射性能,而且能显著提高设计效率。在四维天线阵的系统应用基础方面,充分利用四维天线阵具有边带辐射的特性,将中心频率和多个边带频率信号应用于空间谱估计中。首先,考虑四维天线阵列形式随时间变化的特点,改进MUSIC算法以利用边带信号而不是各单元接收的信号构成信号空间。其次,将DE/BEGA算法与MUSIC算法相结合,在多种时间调制方式下提高可分辨概率、降低均方根误差并抑制伪峰,实现了对空间谱估计性能的优化,较常规阵列具有显著优势。最后,构建了一个基于四维天线阵的空间谱估计实验平台,完成了在实际环境中对信号的发射、接收以及离散信号处理,通过原理性实验验证了四维天线阵在空间谱估计应用领域的可行性。
[Abstract]:With the rapid development of wireless electronic systems, array antennas play an increasingly important role in improving the overall performance of wireless systems. Array antennas, which are widely used in various electromagnetic environments, often require low sidelobe, multi-beam, beam scanning and beamforming, etc. These performance requirements greatly increase the design difficulty of array antenna and the complexity of feed network, and require the device to have high precision. The four dimensional antenna array with time design degree of freedom can effectively reduce the difficulty of antenna array design and its dependence on the feed amplitude and phase. In addition, the radiation characteristics which are superior to conventional array antennas are more and more explored and paid more attention to. Based on the frequency-domain characteristics of four-dimensional antenna array, this paper studies the efficient design of four-dimensional antenna array and the basis of system application. The main contents of this paper are as follows: in the aspect of high efficiency design of four dimensional antenna array, a bit by bit evolutionary genetic algorithm is proposed to solve the efficiency problem in the switching sequence optimization design of four dimensional antenna array. Considering the characteristic of periodic time modulation, the mathematical expression of switch timing is combined with the physical meaning. The algorithm takes each gene in the chromosome as an independent evolutionary unit, and introduces the concept of gene retention probability. By preserving high-quality genes and reversing inferior genes, all individuals in the population can be used to promote gene evolution together. By combining with the physical meaning, the algorithm improves the direction of iteration significantly, and has better optimization ability than the existing algorithms for the design of large array with a large number of parameters. A large number of simulation experiments show that applying bit by bit evolutionary genetic algorithm to the optimization design of four-dimensional antenna array can not only obtain better radiation performance, but also improve the design efficiency significantly. On the basis of the system application of four-dimensional antenna array, the center frequency and multiple sideband frequency signals are applied to the spatial spectrum estimation by making full use of the sideband radiation characteristics of the four-dimensional antenna array. Firstly, considering the variation of the antenna array form with time, the MUSIC algorithm is improved to make use of the sideband signal instead of the signal received by each unit to form the signal space. Secondly, the DE/BEGA algorithm and MUSIC algorithm are combined to improve the resolution probability, reduce the root mean square error and suppress the pseudo peak under various time modulation modes. The performance of spatial spectrum estimation is optimized and has a significant advantage over the conventional array. Finally, an experimental platform of spatial spectrum estimation based on four-dimensional antenna array is constructed, and the signal transmitting, receiving and discrete signal processing are completed in the actual environment. The feasibility of four dimensional antenna array in the application of spatial spectrum estimation is verified by theoretical experiments.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN820.15

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