共查询到19条相似文献,搜索用时 140 毫秒
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本文运用遗传算法(GA)综合稀疏阵列(单元从规则栅格中稀疏)时,不仅优化单元间距,而且将单元激励也作为优化变量,从而提供了更多的自由度来控制稀疏阵列的性能.其中,单元的幅相加权在数字波束形成天线中可以很容易通过数字方法实现.由于稀疏阵列间隔是栅格的整数倍,因此采用了GA结合快速傅立叶变换的方法加快阵列方向图的评估,提高了优化效率. 相似文献
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提出了利用遗传算法(GA)结合快速傅立叶变换(FFT)方法来进行阵列失效的校准,通过引入傅立叶变换的变换域和角域的映射,在变换域中利用FFT计算个体阵列的阵因子,减少了GA评估个体的时间,从而大大提高了失效校准的速度。以一个-35分贝副瓣电平的32单元阵列为例,校准一单元失效和二单元失效的时间都减少了至少一个数量级,算法也可应用于两个以上单元失效的情况。 相似文献
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针对近场条件下数字阵列雷达导向矢量幅相非一致性对自适应波束形成(adaptive beamforming,ADBF)算法性能的影响,通过构建近场多通道数字阵列雷达回波信号模型,分析近场多通道信号二维频谱,发现在近场条件下带限干扰信号的频谱会出现非均匀分布,呈现周期性栅格分布特征,造成算法性能下降.本文提出一种具有全新干扰样本选择策略的近场ADBF(near field ADBF, NF-ADBF)算法,通过寻优干扰信号频谱栅格边界,在栅格区间进行多门限样本筛选,离散提取干扰信号样本,构建完备的干扰信号协方差矩阵,提升近场条件下的自适应处理性能.通过在地面搭建仿真试验环境,模拟典型的数字阵列近场工作环境,通过录取试验数据分析并与理论仿真进行对比,验证了近场干扰样本筛选策略和NF-ADBF算法模型的有效性. 相似文献
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本文首先对遗传算法进行改良,并精心设计了适应函数,以确保遗传算法快速收敛;然后,应用改良后的遗传算法对天线单元正三角形排列的六边形平面阵进行优化稀疏布阵处理,以改善其辐射特性.本文还研究了优化稀疏阵的频率特性,并提出了仅对阵列天线外边缘部分进行优化稀疏处理以达到改善整个阵列天线辐射特性的方法,该方法具有优化区间小和计算量少等优点,为以改善性能和降低造价为目的的大型阵列天线优化稀疏处理提供了一条有效途径.结果表明通过优化稀疏处理,六边形平面阵的辐射特性可以获得相当大的改善,天线阵的最大旁瓣电平降低了7.5~9.4dB,仅对阵列天线外边缘部分单元进行优化稀疏处理可以达到与对全部单元进行优化稀疏处理相同的性能改进. 相似文献
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在许多工程应用中,天线阵列要求有窄的扫描波束,而不要求有相应的增益,因此可以采用稀疏阵列。阵列如果周期性变稀会使方向图出现非常高的副瓣,这可以通过破坏非周期的方法加以控制。提出利用高斯随机分布的密度函数设置稀疏阵列,在稀疏阵列得到的协方差矩阵经扩展后,增益有了明显的提高。比较了该阵列扩展前和扩展后的测向性能,分析了阵列在不同稀疏比下的测向性能以及波束图,可以看出稀疏阵列的波束图的旁瓣明显降低了。 相似文献
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基于遗传算法的载体上共形天线阵列优化 总被引:1,自引:0,他引:1
基于载体上共形天线相控阵列的优化综合由于计算时间长,一般不会采用GA方法优化,主要原因就是个体适应度的计算通常需要对整个天线阵列进行一次全波分析.但是本文预计算单元在阵列环境中方向图,利用相控阵理论中的单元在阵列环境中的方向图直接叠加的方法,计算个体适应度,可以大大加快求解个体适应度的速度,为直接使用GA方法优化共形天线阵列提供了可能.该方法既考虑了载体的影响又考虑了单元之间耦合的影响.通过数值实验可以看出,该方法能够大大的加快优化速度,而且优化结果与全波分析的结果能够很好的吻合. 相似文献
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针对稀疏阵列下2维波达方向(DOA)估计问题,该文提出一种基于稀疏采样阵列优化的加速逼近梯度(APG)算法与多重信号分类(MUSIC)算法相结合的2D-DOA估计方法。首先,建立稀疏阵列下的2D-DOA估计信号模型,并证明其具备低秩特征,满足零空间性质(NSP)。其次,为提高稀疏阵列下矩阵填充方法重构接收信号矩阵性能和以此为基础的2D-DOA估计精度,提出基于遗传算法(GA)的稀疏采样阵列优化方法。最后,将APG和MUSIC算法相结合,在重构完整平面阵列接收信号矩阵的基础上完成2维波达方向估计。计算机仿真结果表明,该方法在保证2维波达方向估计精度前提下,大幅提高阵元利用率,有效降低空间谱平均旁瓣,与常规2D-DOA估计方法相比具有优势。 相似文献
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基于自适应稀疏阵的结构,提出了一种具有宽视角与稳定扫描波束分辨率性能的相控阵天线。阵列单元是可以在相同谐振频率下实现TM;和TM;两种模式共同工作的单激励圆环贴片天线,其具有140°的半功率波束宽度,这种宽波束辐射效果能够较好地拓展相控阵天线的扫描范围。基于此单元构建了一个35元线阵,对其波束扫描分析发现在限定增益波动小于2 dB的条件下阵列扫描范围可以达到-70°~+70°,但主瓣波束宽度随着扫描角度的增加而增大。为解决这个问题,引入了自适应稀疏阵的概念,并采用基于互耦补偿矩阵的迭代快速傅里叶变换(Iterative Fast Fourier Transform,IFFT)技术进行自适应稀疏阵的优化设计。结果表明,所提出的基于自适应稀疏阵结构的35单元相控阵天线在-60°~+60°扫描范围内增益波动始终小于1.5 dB,波束宽度波动小于1°,且峰值旁瓣电平基本保持在-20 dB以下。相较于均匀周期阵列,所提出的自适应稀疏相控阵天线能够在实现低旁瓣宽视角扫描的同时,有效提高天线在宽角度范围内扫描波束分辨率的稳定性。 相似文献
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The use of asymmetrical element spacings in thinned aerial arrays is shown to give symmetrical radiation patterns. The use of asymmetrical element spacings gives lower sidelobe levels than symmetrical spacings. With an array of nine elements in a 19? array, the greatest sidelobe level is reduced from ?5.61 dB to ?6.87 dB by using an asymmetrical array instead of a symmetrical array. 相似文献
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在推导出栅格天线阵列方向图的基础上,提出一种基于遗传算法的栅格天线阵旁瓣电平优化的方法。此方法首先简化栅格天线阵物理模型,给出等效模型下的阵列方向图,然后以栅格天线阵的短边电流幅度为优化参量,以阵列天线方位面的副瓣电平为适应度函数,利用遗传算法的最优化搜索得到满足副瓣要求的电流幅度,再通过电流幅度计算辐射单元阻抗,最终设计出满足要求的低旁瓣栅格天线阵。为了验证该方法的有效性,对一种频扫微带栅格天线进行了优化,在电磁仿真软件中对优化后的天线进行了仿真,根据设计结果加工制作了原型天线并进行了测试,测试结果显示优化后天线阵的副瓣电平降低了5dB,优化效果明显。 相似文献
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Gopi Ram 《International Journal of Communication Systems》2021,34(1):e4614
Optimal design of antenna arrays to minimize the mutual coupling effects in the geometrical arrangements of the linear antenna array (LAA) and circular antenna array (CAA) is dealt with in this work. Two different cases are considered to reduce the effect of LAA and CAA: Case‐1 in which the current excitations of the antenna array are considered to get the optimal radiation pattern of two geometry called LAA and CAA and Case‐2 in which inter‐element spacing and current excitations are both optimized for LAA geometry. A cost function that involves the mutual coupling factor as an optimization factor is developed to reduce the side lobe level (SLL), which takes mutual coupling effects into consideration. Excitation values and inter‐elemental spacing are optimized using particle swarm optimization (PSO). In LAA, for 8‐, 12‐, 16‐element arrays, SLLs are reduced by ?15.52, ?16.71, and ?17.78 dB in Case‐1. For the same sets of element arrays, SLLs were reduced by ?17.35, ?19.71, and ?20.26 dB in Case‐2. In CAA, the current excitations of the antenna array are optimized. For 8‐, 12‐, and 16‐ element arrays, SLLs are reduced to ?7.405, ?10.52, and ?9.43 dB, respectively. The arrays coded with the help of MATLAB based computation and the results obtained by MATLAB are validated by using CST. 相似文献
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On the empirical optimization of antenna arrays 总被引:2,自引:0,他引:2
Empirical optimization is an algorithm for the optimization of antenna array performance under realistic conditions, accounting for the effects of mutual coupling and scattering between the elements of the array and the nearby environment. The algorithm can synthesize optimum element spacings and optimum element excitations. It is applicable to arrays of various element types having arbitrary configurations, including phased arrays, conformal arrays and nonuniformly spaced arrays. The method is based on measured or calculated element-pattern data, and proceeds in an iterative fashion to the optimum design. A novel method is presented in which the admittance matrix representing an antenna array, consisting of both active and passive elements, is extracted from the array's element-pattern data. The admittance-matrix formulation incorporated into the empirical optimization algorithm enables optimization of the location of both passive and active elements. The methods also provide data for a linear approximation of coupling as a function of (nonuniform) element locations, and for calculation of element scan impedances. Computational and experimental results are presented that demonstrate the rapid convergence and effectiveness of empirical optimization in achieving realistic antenna array performance optimization. 相似文献
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Numerical annealing of low-redundancy linear arrays 总被引:7,自引:0,他引:7
An algorithm is developed that estimates the optimal distribution of antenna elements in a minimum redundancy linear array. These distributions are used in thinned array interferometric imagers to synthesize effective antenna apertures much larger than the physical aperture. The optimal selection of antenna locations is extremely time consuming when large numbers of antennas are involved. This algorithm uses a numerical implementation of the annealing process to guide a random search for the optimal array configuration. Highly thinned low-redundancy arrays are computed for up to 30 array elements. These arrays are equivalent to the optimal solutions that are known for up to 11 elements. The arrays computed for 12-30 elements have the fewest redundancies reported to date 相似文献