共查询到18条相似文献,搜索用时 171 毫秒
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阵列天线综合一般是基于理想的单元天线方向图,而不考虑阵元间的互耦。本文提出了一种考虑互耦的基于遗传算法的阵列天线综合方法。该方法首先利用商用仿真软件分别计算阵列中各个阵元在阵列中的方向图,再通过遗传算法优化出目标方向图。通过实例比较可以看出,这种方法能够比较精确的仿真计算阵列的方向图,易于在工程上实现高性能的天线阵列系统。 相似文献
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六个单极对数周期天线单元组成的轴对称圆形阵列天线,能在超宽频带内产生正交双极化的和、差方向图.首先从理论上分析了任意极化方向的点源天线组成的非相似圆形阵列的方向图,结果表明:圆形阵的直径满足0.25λ~0.5λ时,和方向图的Eθ分量-10 dB波束宽度约为130°~100°,可作为超宽频带抛物面单脉冲天线的照射器.以点源阵的分析结果为指导,设计了工作频率为1~8 GHz的单脉冲天线,并结合HFSS软件的仿真结果对阵列参数进行了优化.给出了圆形天线阵的驻波以及方向图的实测结果,在0.85~8.5 GHz范围内,照射器的驻波比小于2.5. 相似文献
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针对直线阵列天线稀疏优化中的遗传算法进行研究,给出了一种稀疏直线阵列的优化模型,介绍了遗传算法的理论,通过算法仿真,对稀疏直线阵列的方向图特性进行研究.以方向图最大副瓣电平为适应度函数,得出结论:在稀疏阵列中阵元分布呈中心聚集态势,稀疏率、种群大小和约束条件等,均会对稀疏后阵列方向图特性产生影响;遗传算法适用于稀疏优化... 相似文献
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以离散有限长复指数和的计算为基础,讨论了二雏阵列的方向图问题.通过引入分布函数的概念,可知离散有限长复指数和为其分布函数离散傅里叶变换在1点的值.基于此结论,分析了二维阵天线阵元分布于天线方向图之间的关系:二雏阵列任意方向的方向图为其在该方向分布函数的离散傅里叶变换,该分布函数可通过统计其投影在该方向的临近区域处阵元数目获得.然后,通过对混合圆形阵列天线方向图的分析,验证了该关系的正确性,并说明了上述关系在分析阵列方向图的应用.在此基础上,进一步分析了阵元权重系数对方向的影响,发现该方法与通过改变阵列天线阵元分布的方法等效.最后,提出了基于分布函数的圆形阵列方向图优化方法,并通过仿真实验验证了该方法的可行性.该方法可通过改变圆形阵列阵元沿径向的权重系数使得其对应的任意方向的方向图与期望的窗函数近似. 相似文献
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通过对Cantor集线阵及其补集、同心圆环分形阵的阵列因子方向图特性的分析,指出大间距的分形阵列方向图具有高副瓣的缺点,提出了通过分形阵列阵元的锥削密度加权和少量大间距单元幅度加权相结合的方法来抑制副瓣,改善分形阵的方向图性能,给出了两种具有分形特点的高效率、低副瓣阵列形式和实际测试结果,为分形天线阵列的工程化应用提供了思路。 相似文献
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研究了双圈圆阵在两种不同放置情况下的方向特性, 主要包括阵列方向图的指向、主瓣波束宽度和副瓣峰值电平等.首先, 建立了双圈圆阵的阵列模型, 推导方向图公式并推广到多圈圆阵的情况, 随后对其进行了理论分析.其次, 通过大量仿真实验, 分析了主瓣的半功率点波束宽度和副瓣峰值电平以及扫描角分别与内、外圈阵元数以及内、外圈阵元半径之间的关系.最后, 对理论分析和仿真结果进行综合梳理, 发现在阵元内、外半径之比为0.5左右时副瓣电平最低, 波束宽度会随着内圈阵元数增大而增大, 随外圈阵元数增大而减小等结论.实验结果可为实际工程应用中合理设置阵元数目以及阵元位置提供理论参考. 相似文献
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Weily A.R. Esselle K.P. Bird T.S. Sanders B.C. 《Antennas and Propagation, IEEE Transactions on》2006,54(8):2263-2274
A technique is described for creating linear array antennas that conform to the natural stacking sequence of the woodpile electromagnetic bandgap (EBG) material. Each element in the linear array consists of a woodpile EBG sectoral horn antenna. The electromagnetic confinement mechanism within each horn antenna relies wholly on the 3-D EBG of the woodpile material. The array element has a typical sectoral horn pattern with a directional beam in one principal plane and a broader beam in the other. The bandwidth of the sectoral horn is almost equal to that of the defect EBG waveguide. Measured and theoretical results for radiation patterns, impedance bandwidth and gain of a sectoral horn antenna made from alumina are described, and theoretical results for a design made from silicon are presented. It is shown that the layer-by-layer nature of the woodpile EBG material enables sectoral horn antennas to be easily stacked together in the E-plane to create linear arrays. Analysis of the mutual coupling as a function of element separation and its effect on reflection coefficient are presented for a two-element linear array in silicon. Theoretical analyses for fixed and scanned beam linear arrays of silicon woodpile EBG sectoral horns are described and finite-difference time-domain results are compared with array theory. The fixed beam arrays are designed for high directivity while the scanned beam array enables wide angle beam steering through the use of parasitic array elements. 相似文献
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Antenna array optimization by a biquadratic programming method is formulated with variable-phase (analog and digital) and constant amplitude excitation. The method can optimize an antenna performance index expressible as a ratio of Hermitian quadratic forms. Power gain optimization and least-squares pattern synthesis with a specified gain are illustrated. Linear, planar, and circular arrays with dipole or circular loop elements are optimized, taking mutual coupling effects between antenna elements into account. The method shows much more rapid convergence characteristics than the Rosenbrock (1960) and Fletcher-Power (1963) methods 相似文献
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电磁异向介质在阵列天线中的应用研究 总被引:1,自引:0,他引:1
为了抑制阵列天线单元的表面波,并减小阵元间的耦合效应,研究了电磁异向介质材料在抑制阵列天线互耦效应中的应用. 基于开口谐振环(Split-Ring Resonator,SRR)负媒质材料特性,将SRR结构单元加载于阵列天线之中,提出了具有互耦抑制效应的天线设计方法. 仿真结果表明:加载SRR结构单元后,天线谐振工作频点处的耦合系数降低了8.8 dB,即由原来的-16.3 dB降低到了-25.1 dB,而对天线阵列的增益和方向图没有太大的影响,可以满足工程的基本要求. 为设计低耦合的微带阵列天线提供了理论支持. 相似文献
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Large closed-curve antenna arrays have been a subject of research for many years and have been shown to have many interesting properties. The paper investigates some of the properties of such a dipole array when the closed curve is a circle. Recently, because of its unique horizontal field pattern, a 90-element circular array of this type has been proposed as a microwave beacon for the coastal navigation of ships and airplanes. In the design of these arrays, it is suggested that the array be rotated mechanically. The question arises: can the mechanical rotation be replaced by an electronic rotation? We show that electronic rotation is not possible for the 90-element circular array originally described, but is possible for a modified array. The subtle difference between these two arrays is clarified and a simple criterion is given for the general case. Also presented is the derivation of an asymptotic formula for the radiation pattern of a resonant circular array of N equal elements with only one element driven. Since the theory for such an array is complicated and involves numerous numerical difficulties, a simple asymptotic formula for the field pattern has advantages over other methods. The simple formula is shown to produce a vertical field pattern that is indistinguishable from its numerically calculated counterpart. Generalization to noncircular arrays is discussed briefly. 相似文献
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矩形栅格平面相控阵天线经常受到圆柱形设备的约束,本文研究设计了一种阵元非均匀分布排列的圆形口径相控阵天线方向图,建立数学模型并对其进行了公式推导和计算机仿真。同时与同等规模的矩形栅格平面相控阵天线方向图进行对比分析。分析表明,前者的半功率点波束宽度要小于后者,主瓣能量利用更加集中,提高了扫描性能,辐射能量大致相同的情况下,前者所需要的阵元数要少,节约了成本。 相似文献
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A 16 x 8 microstrip antenna array with 28 dB of gain at 18 GHz using a parallel-series feed with reduced conductor traces is presented. The feed network connects antenna elements with about 50% reduction in conductor traces compared to conventional arrays with equal numbers of radiating elements. It also enhances the gain-bandwidth performance of the array and maintains a broadside radiation pattern in a wider frequency band. The full-wave simulation results are verified by means of measurements that demonstrate a relative gain-bandwidth of 4.4% with less than 1 dB of gain ripple. 相似文献