一种有阵元间距约束的稀布阵天线综合方法

提出了一种基于改进遗传算法的稀布阵综合新方法,用于优化设计有最小阵元间距约束的稀布线阵.该方法利用个体的实值编码提高了遗传算法的优化效率,通过设计遗传操作预处理和后处理,并采用一种广义的交叉算子和变异算子,有效地避免了基因重组和变异时出现不可行解.在给定阵列孔径和阵元数的条件下,高效地实现了任意最小阵元间距约束下抑制稀布线阵峰值旁瓣电平的稀布直线阵列综合.给出了应用该方法的具体步骤,并通过仿真实验证实了该方法的有效性和稳健性.     

基于实数编码遗传算法的稀布阵列综合

针对有孔径和阵元总数约束的线性阵列,提出了一种基于实数编码遗传算法的稀布阵列综合方法。算法中每条染色体基因主要由阵元间距和激励幅度共同组成,采用双变量组合优化的方式为阵列性能优化提供了更多的自由度。采用十进制实数量化编码的方式,省去了二进制编码过程中的解码运算,使算法程序更为简洁,效率更高。以降低阵列方向图的峰值旁瓣电平为目标函数,运用提出的改进遗传算法针对几种不同的线性阵列进行优化仿真,在同等约束条件下将该算法与其他改进遗传算法进行了优化对比,结果表明该算法表现更为出色。     

稀布圆阵的降维优化方法

针对有阵列孔径,阵元数目和最小阵元间距3种约束下的稀布圆形阵列综合问题,该文提出了一种基于修正遗传算法的降维优化方法。为了充分利用阵元布阵的自由度,同时使稀布阵列满足多个设计约束,在阵元排布时将2维平面阵列优化设计降维成1维的稀布直线阵列,计算阵列性能时再还原为平面阵列。该方法改进了现有圆阵综合方法中轨迹圆半径和轨迹圆上阵元数分布优化的不足,实现了全部阵元的联合优化,降低了算法的复杂性,同时保证了阵列的旁瓣性能,仿真结果证明了该方法的有效性。     

平面稀疏阵列天线的约束优化设计

针对有阵元数和阵列口径约束的矩形平面稀疏阵天线的综合问题,提出了一种基于整数编码的差分进化算法。该方法以每个阵元的栅格位置编号作为设计变量,使阵列的稀疏率满足约束条件,避免了优化过程中的不可行解,还减少了优化变量的个数。为了加速优化过程,采用快速傅里叶变化计算阵列的方向图。以改善阵列峰值副瓣电平为目的进行仿真试验,结果表明：优化后的稀疏天线阵峰值旁瓣电平比现有方法相比改善了1.2~1.7 dB,且具有收敛性和稳定性好的优点。     

基于改进麻雀搜索算法的稀布线阵综合方法

针对阵列天线中阵列孔径、阵元数目、阵元间距等多约束的稀布线阵综合问题,文中提出了一种基于改 进麻雀搜索算法的稀布阵列综合优化方法。给出了改进麻雀搜索算法的流程,并在确定阵列孔径、阵元数目和最小阵 元间距的约束条件下,采用Tent 混沌映射进行天线阵元位置的初始化,提高算法的搜索性和收敛性,实现了抑制天线 峰值旁瓣电平(PSLL)的稀布线阵综合仿真。仿真结果表明,所提出的方法相比于其它文献中的优化方法,能够得到更 低的峰值旁瓣电平,稳健性好,效率高。在仿真结果的基础上,引入实际天线进行组阵分析,验证了该方法的可行性。     

基于自调整映射法则的矩形稀布阵列优化方法北大核心CSCD

针对多约束条件下的矩形稀布阵列优化问题,提出了一种基于自调整映射法则的矩形稀布阵列优化方法。该方法首先提出一种新的最优化问题用于确定阵元坐标矩阵维数以平衡放置阵元数的自由度和阵列孔径可调整空间,并引入用于稀疏阵元的阵元状态矩阵;其次,构建自调整映射法则,对矩形阵列不同方向进行相应的映射,并对阵列短轴方向进行自调整,使得阵元位置满足最小阵元间距,避免出现不可行解;然后,通过粒子群优化算法优化阵元位置得到最优阵元坐标;最后,考虑适应度函数为单波束指向和多波束指向,对算法进行仿真验证。仿真结果发现该算法可以满足多约束条件并有效降低阵列的峰值旁瓣电平,从而提高矩形稀布阵列的性能。     

非均匀线天线阵优化布阵研究

针对有阵元数、孔径和最小阵元间距约束的稀布直线阵列综合问题,提出了一种基于修正遗传算法(MGA)的综合方法.该方法采用真值编码,个体的描述方式可使搜索空间减小,通过设计用于处理约束的矩阵变换和广义的交叉算子和变异算子,有效地避免了基因重组和变异时出现不可行解.在约束阵列孔径和阵元数的条件下,高效地实现了任意最小阵元间距约束下抑制峰值旁瓣电平(PSLL)的稀布阵综合.文中给出了修正遗传算法的流程,该算法的有效性和鲁棒性在稀布阵列综合的仿真实验中得到了验证.     

低峰值旁瓣电平稀布阵综合算法研究

针对稀布阵具有较高峰值旁瓣电平(PSLL)的问题,从阵元对称与否、阵元数奇偶及天线阵列有无栅瓣这三个角度分析、对比了粒子群算法和三种遗传算法进行稀布阵综合的优缺点,并进一步分析了阵元数目、阵列孔径和最小阵元间距对稀布阵PSLL的影响。为进一步降低PSLL,提出在适应度函数中加改进海明窗的方式进行稀布阵阵元位置优化,通过仿真验证了方法的正确性和适用性。     

基于改进遗传算法的非均匀稀布阵列优化

提出了一种对非均匀稀布阵列阵元间距进行优化的改进的遗传算法。该算法在编码时,将阵元间距依据尺寸步长划分为不同的节点,通过对节点的二进制编码,灵活实现带约束阵元间距的遗传编码。在遗传操作过程中,依据不同的进化阶段自适应设定算子系数,有效地提高了遗传算法的收敛性。文中采用同时考虑副瓣电平和渡束宽度的双适应度函数,使优化得到的天线阵列方向图比采用单适应度函数有较好的综合性能。最后通过大量仿真结果验证了这一算法的有效性。     

基于阿基米德螺线的稀布面阵综合方法

提出一种基于改进遗传算法的稀布面阵综合的新方法。该方法通过对阿基米德螺线参数的合理设置,确保了阵元在沿阿基米德螺线的轨迹分布时依然能够满足阵元数约束、孔径约束和最小阵元间距约束,从而将稀布面阵的优化问题转化为非对称线性阵列的稀布问题,这就大大降低了问题的复杂程度。仿真实验结果证明了该方法的有效性。     

平面六边形稀疏阵列天线的优化

针对标准的差分进化算法只能处理连续空间的优化问题,提出了一种基于取整策略的差分进化算法。该方法只需要对优化变量进行四舍五入取整,就能够把标准差分进化算法用于稀疏阵列天线方向图优化。将取整策略的差分进化算法应用到六边形平面稀疏天线阵的布阵设计。为了计算六边形阵列天线的方向图,提出在口径中添加虚拟单元的计算模型,把六边形阵列转化为可以实现二维快速傅里叶变换的矩形阵列。以改善阵列峰值副瓣电平为目的进行仿真试验,结果表明,优化后的稀疏天线阵峰值旁瓣电平与采用遗传算法相比改善了4.5~5.1 dB,且具有计算速度快、稳定性好的优点。     

利用GA实现非对称稀疏线阵旁瓣电平的优化

该文讨论运用遗传算法综合非对称的稀疏直线阵列(阵元从规则栅格中稀疏)。阵元在中心两侧非对称分布的布阵方式提供了可利用的优化自由度,将更有利于提高稀疏阵列的性能。构造了阵元关于阵中心非对称时优化旁瓣电平的适应度函数,仿真结果表明,无对称约束的阵元排列,不仅可以进一步抑制稀疏线阵的相对旁瓣电平(RSLL),而且当阵列由有向阵元组成时,有益于改善阵列波束扫描过程中RSLL的恶化。     

New Model for Synthesis of Symmetrical Thinned Linear Arrays

In symmetrical thinned linear arrays design, the positions of thinned array elements are very important for optimal performance in terms of its minimum peak side lobe level （Msli）. For the synthesis of thinned arrays with a given thinning rate, it would have almost the same Msll solution between taking only segmental aperture nearby both ends of the aperture into account and taking all the aperture into account. In this paper, the element distribution characteristic over the aperture of many optimum thinned arrays is studied, then the aperture release model is founded by the least square method to synthesize the thinned arrays. This model is vital for the computing burden alleviation and the efficiency optimization, and would hardly bring any degradation of the obtained array performance.     

基于跨航向稀疏阵列的机载下视MIMO 3D-SAR三维成像算法

基于阵列天线的SAR 3维成像技术是实现SAR 3维高分辨成像的重要方式之一。该文通过沿飞行平台跨航向稀疏地布置多个收发天线阵列单元,构造了跨航向稀疏下视阵列天线构型的MIMO(多发多收)机载3D-SAR,并分析了跨航向稀疏下视阵列MIMO机载3D-SAR的成像几何、3维回波信号模型,提出了适用于跨航向稀疏下视阵列MIMO机载3D-SAR的3维成像算法,最后通过仿真实验验证了算法的有效性并对结果进行了分析。     

Optimization of thinned aperiodic linear phased arrays using genetic algorithms to reduce grating lobes during scanning

The scan volume of a thinned periodic linear phased array is proportional to the spacing between array elements. As the spacing between elements increases beyond a half wavelength, the scan range of the array will be significantly reduced due to the appearance of grating lobes. This paper investigates a method of creating thinned aperiodic linear phased arrays through the application of genetic algorithms that will suppress the grating lobes with increased steering angles. In addition, the genetic algorithm will place restrictions on the driving-point impedance of each element so that they are well behaved during scanning. A genetic algorithm approach is also introduced for the purpose of evolving an optimal set of matching networks. Finally, an efficient technique for evaluating the directivity of an aperiodic array of half-wave dipoles is developed for use in conjunction with genetic algorithms.     

New Model for Synthesis of Symmetrical Thinned Linear Arrays

In symmetrical thinned linear arrays design, the positions of thinned array elements are very important for optimal performance in terms of its minimum peak side lobe level (Msll). For the synthesis of thinned arrays with a given thinning rate, it would have almost the same Msll solution between taking only segmental aperture nearby both ends of the aperture into account and taking all the aperture into account. In this paper, the element distribution characteristic over the aperture of many optimum thinned arrays is studied, then the aperture release model is founded by the least square method to synthesize the thinned arrays. This model is vital for the computing burden alleviation and the efficiency optimization, and would hardly bring any degradation of the obtained array performance.     

共享孔径同心圆阵稀疏交错优化布阵方法

同心圆阵列天线具有波束对称、360°方位角扫描、抗干扰能力强等优点，被广泛应用于星载、机载、舰载雷达及飞机声呐等领域。在天线孔径有限的情况下，如何进一步提高同心圆阵的孔径利用率，通过孔径的空分复用，设计出子阵稀疏交错分布的多功能同心圆阵列天线，具有较大的研究价值。利用均匀同心圆阵列天线激励与方向图函数存在二维傅里叶-贝塞尔变换关系，基于二维三次插值和密度加权，提出了一种同心圆阵稀疏交错优化布阵的方法。该方法通过对均匀同心圆阵列天线方向图采样值的频谱能量进行分析，采用三次插值的方法，实现了同心圆天线阵列方向图函数到同心圆阵元激励能量的映射转换；基于密度加权的原理，对排序后归一化阵元激励的奇偶交错选取，使得稀疏交错子阵方向图频谱能量均分匹配，实现了同心圆阵的稀疏交错优化布阵设计。仿真结果表明，该方法得到的交错子阵天线具有峰值旁瓣电平低、主瓣宽度窄且方向图性能近似程度高的优点，有效解决了同心圆阵列天线稀疏交错优化布阵的设计难题，实现了两子阵交错的共享孔径多功能同心圆阵列天线设计。     

Construction of thinned phased antenna arrays by coding the positions of array elements in a equidistant grid of nodes on the basis of the properties of prime and composite number moduli

A method for construction of thinned phased antenna arrays (PAAs) by coding the positions of array elements in an equidistant grid of nodes on the basis of the properties of prime and composite number moduli is proposed. (Such arrays are abbreviated as PAA-C.) An algorithm for the arrangement of array elements is described, examples of the arrangement of elements are presented, and the array patterns and their cross sections are calculated. A method for suppression of sidelobes of the PAA-C pattern is proposed. The method is based on the multiplication of the patterns of PAA-Cs differing in their codes corresponding to one modulus or in coding by twin prime numbers.     

An improved thinning method for density tapering of planar array antennas

A thinning method is presented to realize the desired aperture distribution in a planar array antenna with elements fixed on an array lattice. In this method elements to be excited are determined by quantizing cumulative weights which are calculated from the desired aperture distribution. At first, this method is applied to density tapering on orthogonal axes of a planar array. Radiation patterns of the planar array determined by this method are compared with those by the desired amplitude distribution, and the results show good coincidence. Next, this method is extended to density tapering on four axes, that is, orthogonal and diagonal axes of a planar array. Moreover, this method is applied to density tapering with multi-amplitude level elements in order to enhance directive gain of thinned array. Lastly, a rectangular planar array was fabricated, and its radiation patterns were measured. Measured results were in good coincidence with calculated ones, and the usefulness of this method was verified.