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应用实数编码的遗传算法进行阵列天线方向图综合的优化设计.针对阵列天线方向图综合的特点,运用算法,通过优化单元电流幅度、阵元间距,对阵列天线方向图进行了综合优化,其中包括方向图的波瓣控制和零点生成,并同时压低旁瓣电平使其达到期望值.仿真结果表明,通过优化,天线阵的辐射特性获得很大的改善,在主瓣宽度满足要求的情况下,副瓣电平也可达到-33.6100dB.良好的仿真结果表明遗传算法在阵列天线方向图综合中的应用是有效的,有良好的应用前景. 相似文献
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针对粒子群优化(PSO)算法在处理复杂优化问题时,容易早熟收敛的问题,将比例控制器用于粒子群算法种群聚集度控制.粒子种群可以在任一聚集范围内保持任意时间的搜索,这样能够更好地平衡种群聚集度和搜索精度,从而提高PSO算法处理复杂优化问题的效率.对多零点和低旁瓣约束情况下的阵列天线方向图优化进行仿真实验,结果表明所提算法可在处理复杂优化问题上取得更好的优化效果. 相似文献
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研究阵列天线性能优化设计,针对阵列天线幅相误差对天线性能的影响,传统的阵列天线容差分析采用统计理论方法,前提需要假设幅相误差服从某种概率分布,导致不同分布的幅相误差对应不同的结论形式,并且公式推导过程复杂.为了在建立阵列天线最坏情况容差分析的数学模型,提出了一种混沌粒子群算法简单实用的阵列天线最坏情况容差分析方法.通过在粒子群算法中利用混沌技术优化初始种群,并对位置更新时引入混沌扰动项和位置更新后进行边界约束,进行仿真,提高了粒子群算法的全局搜索能力.结果验证了算法在最坏情况分析时,可以得到在准确性和稳定性方面的优化结果. 相似文献
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针对宽带任意阵列天线的方向图综合问题,提出了基于凸优化及其求解软件的方向图综合方法.其中针对宽带最低旁瓣方向图综合问题的特殊性,利用了凸优化的优良数值求解特性,以及最新的凸优化求解软件cvx时任意阵列天线的宽带最低旁瓣方向图综合算法进行了有效的建模和求解,获得了满足给定要求的宽带综合方向图.并通过详细的仿真分析验证了所提方法的正确性和有效性,而且优于当前提出的迭代算法. 相似文献
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为了降低稀布阵列的峰值旁瓣电平并抑制稀布阵列的栅瓣,提出了一种多目标粒子群与凸优化相结合的方向图综合算法。该算法将多目标粒子群优化(Multi-objective particles swarm optimization,MOPSO)作为全局搜索器,凸优化算法作为局部搜索器来搜索最优解,优化的变量不仅是阵元的权值,而且还加入了阵元位置这一参数,从而能够提供更多的自由度来控制稀布阵列的性能。基于30阵元的稀布圆形阵列的仿真结果表明:与单纯使用MOPSO算法相比,本文提出的用MOPSO算法优化阵元位置,凸优化算法优化阵元权值的联合优化算法,得到的栅瓣和峰值旁瓣电平都小于-19.3 dB。 相似文献
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多重信号分类算法在共形阵列天线中的应用 总被引:1,自引:0,他引:1
在天线信号优化设计中,传统的共形阵列天线的信号波达方向(DOA)估计采用了波束扫描技术,需要大量的阵元才能获得较高分辨率,对于有限的阵列孔DOA估计来说,上述技术的分辨率会受到瑞利限制.而多重信号分类(MUSIC)算法,由于充分利用了噪声子空间和信号子空间的正交性,构造了空间谱函数,可以通过谱峰值的搜索来达到DOA估计.对MU-SIC及改进算法进行分析,并且分别在均匀线阵,柱面阵列和锥面阵列天线模型下进行了仿真,结果表明,阵列的排列方式对波达方向的估计性能具有重要的影响. 相似文献
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In this article, cylindrical and conical conformal arrays are presented to flexibly launch the OAM vortex beams. First, we analyze the characteristics of OAM beams generated by planar annular arrays with different radii. Then characteristics of vortex waves generated by cylindrical and conical arrays with different curvatures are analyzed. Finally, prototypes of cylindrical and conical arrays are fabricated and measured. Experimental results imply that OAM vortex beams can be effectively generated by cylindrical and conical conformal phased arrays, which may provide a reference for electromagnetic vortex communication on the conformal carrier in the future. 相似文献
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This article determines the near optimal conformal antenna array structure for direction‐of‐arrival (DOA) estimation through a comprehensive study on the planar and usual conformal antenna arrays including the cylindrical and hemispherical by using the directive antenna elements in all designs. To model the hemispherical structure, an improved multi‐face antenna array with three different tilts is proposed and compared with previous works in order to investigate the tilt effect and obtain the conclusive results. The Cramer‐Rao lower bound, multiple signal classification, and root‐mean‐square error algorithms are utilized to evaluate the estimation accuracy of all conformal structures. Finally, by comparing the estimation precision of all conformal structures it is shown that the purposed multi‐face structure as the hemispherical model has a better performance than other conformal structures in terms of the maximum angular coverage of the spatial resource. Moreover, the proposed study method in this article fully examines the impacts of the different conformal antennas geometric structure on the DOA estimation performance by involving the directive antennas radiation patterns. 相似文献
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一种改进的共形阵方向图综合方法 总被引:1,自引:0,他引:1
与传统阵列相比,共形阵安置更为灵活,应用更为广泛。然而,针对共形阵的方向图综合也更为复杂。传统的方向图综合方法对共形阵并不适用。通过在旁瓣区域施加虚拟干扰能够有效实现共形阵的方向图综合。如何通过迭代过程控制虚拟干扰功率的大小成为该方法的关键。现有的迭代方法一般存在收敛缓慢或计算复杂的问题。
本文基于线性约束最小方差准则,提出了一种改进的共形阵方向图综合方法。该方法适用于
任意阵型的方向图综合。仿真实验证明,该方法能加快收敛速度,并降低自适应波束形成器
对迭代系数的依赖性。 相似文献
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In this article, an extended particle swarm optimization (EPSO) algorithm is proposed for designing conformal phased arrays. On the basis of traditional particle swarm optimization (PSO), novel velocity updating mechanism, new exceeding boundary control operator, and global best perturbation are introduced in EPSO to overcome the drawbacks of PSO. To validate the efficiency of the proposed algorithm, both the classical test functions and the scenarios concerning a 1 × 9‐element cylindrical conformal phased array and a 3 × 9(27)‐element cylindrical conformal array with flat‐top shaped‐beam pattern are presented. Simulation results show that the proposed method is superior to genetic algorithm (GA) and PSO when applied to both the classical test functions and the practical problems of conformal antenna array synthesis. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. 相似文献
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Abramson A.R. Woo Chul Kim Huxtable S.T. Haoquan Yan Yiying Wu Majumdar A. Chang-Lin Tien Peidong Yang 《Journal of microelectromechanical systems》2004,13(3):505-513
This paper discusses the design, fabrication and testing of a novel thermoelectric device comprised of arrays of silicon nanowires embedded in a polymer matrix. By exploiting the low-thermal conductivity of the composite and presumably high-power factor of the nanowires, a thermoelectric figure of merit, higher than the corresponding bulk value, should result. Arrays were first synthesized using a vapor-liquid-solid (VLS) process leading to one-dimensional (1-D) growth of single-crystalline nanowires. To provide structural support while maintaining thermal isolation between nanowires, parylene, a low thermal conductivity and extremely conformal polymer, was embedded within the arrays. Mechanical polishing and oxygen plasma etching techniques were used to expose the nanowire tips and a metal contact was deposited on the top surface. Scanning electron micrographs (SEMs) illustrate the results of the fabrication processes. Using a modification of the 3/spl omega/ technique, the effective thermal conductivity of the nanowire matrix was measured and 1 V characteristics were also demonstrated. An assessment of the suitability of this nanocomposite for high thermoelectric performance devices is given. 相似文献
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Pattern synthesize of conformal array antennas is often a challenging problem. Various optimization algorithms such as genetic, particle swarm optimization (PSO), and invasive weed optimization have already been used for pattern synthesizing of conformal arrays. In this paper, a focused beam is synthesized for a quarter cylindrical conformal array antenna using the PSO algorithm with small computations. The desired pattern is a focused beam at θ = 90° and ? = 45° with 10° beamwidth in elevation and 15° beamwidth in azimuth with ?20 dB side‐lobe level. This method can be used in general for synthesizing arbitrary desired patterns and array geometries. 相似文献
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针对干扰方向在某个角度区域内不能精确估计的工程实际问题,可应用宽凹陷波束赋形技术提高信噪比。根据共形球面天线阵列的阵元位置分布,提出了一种适用的宽凹陷波束赋形和凹陷宽度计算机测量技术。建立了该优化问题的适应度函数模型并应用遗传算法优化设计了赋形波束,仿真结果论证了遗传算法进行波束赋形和测量的有效性和稳健性,并拟订了波束凹陷宽度的计算机测量系统。 相似文献
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Regression conformal prediction produces prediction intervals that are valid, i.e., the probability of excluding the correct target value is bounded by a predefined confidence level. The most important criterion when comparing conformal regressors is efficiency; the prediction intervals should be as tight (informative) as possible. In this study, the use of random forests as the underlying model for regression conformal prediction is investigated and compared to existing state-of-the-art techniques, which are based on neural networks and k-nearest neighbors. In addition to their robust predictive performance, random forests allow for determining the size of the prediction intervals by using out-of-bag estimates instead of requiring a separate calibration set. An extensive empirical investigation, using 33 publicly available data sets, was undertaken to compare the use of random forests to existing state-of-the-art conformal predictors. The results show that the suggested approach, on almost all confidence levels and using both standard and normalized nonconformity functions, produced significantly more efficient conformal predictors than the existing alternatives. 相似文献