共查询到20条相似文献,搜索用时 156 毫秒
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将Gram-Schmidt正交化方法应用到线性阵列天线方向图综合中.此方法对阵元结构和类型都没有要求,具哌有很强的通用性.针对实际设计中阵结构不同以及对波束图的要求多种多样,该方法在具体设计过程与计算步骤上有不小的差别.通过对普通Chebyshev加权阵和Dolph-Chebyshev阵为例的详细设计,证明了此方法的有效性和高效性. 相似文献
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分解大型阵列为关于阵列中心对称的两个子阵,对内子阵进行阵元位置微扰形成指定零陷。借助对微扰后方向图的泰勒展开进行线性化,以微扰后方向图形变最小化为目标,将指定方向控零的约束条件分实部、虚部分别约束微扰值,运用方向导数法快速求解出微扰值,实现了在指定方位快速控零,并提出引入小值控制零陷深度。方法不改变阵列孔径,在指定方向控零后能维持原主波束形状、副瓣水平不变,仿真表明本方法的有效性和优越性。 相似文献
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天线阵辐射图型强制零点控制,由于对定向干扰抑制的有效性,已成为天线阵辐射图型综合理论中心课题之一。本文围绕着这个课题,对三维天线阵辐射圈的零点控制进行了研究,它包括:用矢量空间方法,分析了多重零点控制的基本关系;根据零点本身的扩展性,引入了零域的概念,提出了多重强制零域的生成方法;导出了多重零点控制辐射图型的分解公式;揭示了由主波束和多个零点强制波束合成多重强制零点辐射图型的基本规律;给出了数值结果并进行了讨论;把这一分解原理与自适应成零天线阵辐射图型进行了类比。 相似文献
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The paper presents a new approach to spatial derivative constraints for the generalized sidelobe canceller (GSC). Spatial derivative constraints have been applied to linearly constrained minimum variance beamformers to reduce the sensitivity to steering error. Earlier approaches to this problem constrained derivatives of the beamformer power and phase response, leading to beamformer performance that depended on the coordinate reference location of the array. Current approaches constrain only the beamformer power response, eliminating the problem with phase dependence. However, nonlinear minimization is required in order to solve for the linear constraint equations. An alternative approach for the GSC, which is presented in the paper, is to use derivative constraints to flatten the null of the spatial blocking filter power response. Thus, for a small steering error, the desired signal is still blocked from the noise cancelling filter, and the GSC output is unaffected by the steering error. These derivative constraints can be used with wideband array calibration, leading to effective performance in the presence of array errors. This same approach to derivative constraints can be used in other applications involving spatial blocking filters, such as the constrained MUSIC direction finding algorithm to give robustness against direction error of the known signal subspace 相似文献
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The least mean square pattern synthesis method is extended to include constraints such as pattern nulls or pattern-derivative nulls at a given set of angles. The problem is formulated as a constrained approximation problem which is solved exactly, and a clear geometrical interpretation of the solution in a multidimensional vector space is given. The relation of the present method to those of constrained gain maximization and signal-to-noise ratio (SNR) maximization is discussed and conditions for their equivalence stated. For a linear uniformN -element array it is shown that, whenM single nulls are imposed on a given "quiescent" pattern, the optimum solution for the constrained pattern is the initial pattern and a set ofM -weighted(sin Nx)/sin x -beams. Each beam is centered exactly at the corresponding pattern null, irrespective of its relative location. For the case of higher order nulls, then th pattern derivative is similarly canceled by then th derivative of a(sin Nx)/sin x -beam. In addition, simple quantitative expressions are derived for the pattern change and gain cost associated with the forced pattern nulls. Several illustrative examples are included. 相似文献
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传统阵列方向图宽零陷形成技术需要对阵元施加复加权或者阵元位置扰动等复杂操作,实际实现比较困难。提出了一种基于遗传算法的唯相位波束赋形方法,针对宽零陷特点,结合均匀线阵方向图数学模型,设计一种适应度函数,优化阵元相位扰动值,最终获得符合要求的宽零陷阵列方向图。仿真结果表明,该方法可以在唯相位条件下形成较深的宽零陷,且零陷较平坦,收敛速度较快,稳健性较好。 相似文献
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Goudos S.K. Miaris G.S. Sahalos J.N. 《Antennas and Propagation, IEEE Transactions on》2001,49(2):298-303
A method for the geometry synthesis of a linear array is presented. We start from an initial array with quantized amplitudes. After this, we perturb the element positions by combining an iterative technique with the orthogonal method. The final position of the elements is found from the last iteration where the desired approximation of the pattern is obtained. Arrays with more constraints on the pattern need more quantized amplitudes. Several examples for different cases show the applicability of our method 相似文献
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Minimum p-error design of nonuniformly spaced linear array 总被引:3,自引:0,他引:3
《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1984,72(11):1654-1655
A design method which minimizes the p-error of a weighted array pattern for nonuniform linear array is studied. The Fletcher-Powell method is used to find the minimum set of sensor locations. With uniform weight and large p, the result has sidelobes of almost equal level. In addition, an array pattern with null(s) at some specified value can be designed with proper choices of weights. 相似文献
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On the constrained synthesis of array patterns with applications to circular and arc arrays 总被引:1,自引:0,他引:1
Synthesis of array patterns involving optimization with linear and nonlinear constraints is considered. The general solution for the composite weight vector can be decomposed into a part which satisfies the linear constraints and another lying orthogonal to it. This decomposition is shown to yield simple solutions to several beam optimization problems including some with nonlinear constraints. A geometrical derivation of this result is presented which also provides new insights into the mechanism of null-steering via linear constraints. Application of this approach in conjunction with some search algorithms to the synthesis of optimum array patterns with prescribed narrow or broad nulls is shown to yield interesting and useful solutions. The results are illustrated by considering the design of "circular" and "arc" arrays. 相似文献
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Miaris G.S. Goudos S.K. Iakovidis C. Vafiadis E. Sahalos J.N. 《Antennas and Propagation Magazine, IEEE》2002,44(5):62-74
A computer tool (ORAMA) for the synthesis of linear antenna arrays is presented. The orthogonal method (OM) and the orthogonal perturbation (OP) method are used. The orthogonal method derives the excitation of the elements of the array, while the orthogonal perturbation method quantizes the excitation and determines the position of the elements. The user has the options to select the array geometry, the case study for a specific desired pattern, the method to be used, and the element type. Several design cases with various constraints are presented. ORAMA (a demo of the software is available at http://rcl.physics.auth.gr) has been designed as a Windows MDI application for the academic classroom, as well as for professional antenna engineers. A set of examples for different array patterns shows the usefulness of the tool. 相似文献
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本文研究了利用凸规划方法综合稀疏随机阵方向图的问题,采用最大信号干扰加噪声比准则,利用附加的线性约束对旁瓣作进一步控制,将方向图设计问题分别转化为二次规划和二次锥规划形式,再用内点法求解。该方法应用于不同形式的稀疏阵列方向图综合,获得了良好的结果。 相似文献
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The orthogonal method for geometry synthesis of a linear antenna array is presented. We start from an initial array, and we perturb the element positions by using an iterative procedure and applying the orthogonal method. Applications for arrays with uniform excitation give patterns with the desired sidelobe level 相似文献