超宽带低副瓣赋形反射面天线研制

本文介绍超宽带低副瓣赋形反射面天线的实验研究。经实测,研制的天线在Ｓ波段大于２５％的带宽内,水平面最大副瓣电平均值小于－３１ｄＢ,垂直面具有超余割平方波束,天线系统电压驻波比小于１．２３。同时,在更宽的频带内该仍然上仍十分优异的电气性能。     

任意阵列的低副瓣宽凹口仅振幅加权口面综合的实数算法

本文给出了一种仅振幅加权的宽凹口低副瓣的口面综合的实数算法,它基于“单元零点向量法”和Ｇｒａｍ—Ｓｃｈｍｉｄｔ正交化方法,此算法能够适用于任意复杂口径天线阵列（包括一维、二维和三维情况）。作为举例,本文给出了此算法对线阵、圆周阵和椭圆周阵的模拟计算结果,结果证明了本算法是行之有效的。     

一种改进的环形阵列低副瓣数字波束实现方法

本文提出了一种改进的基于数字波束形成的环形阵列低副瓣实现方法。该方法使用左右第一副瓣之间角度范围内的相位均值作为阵列单元初相,从而减小此角度范围内的加权相位偏差,进而避免由于相位恶化带来的副瓣抬高,最终实现阵列的-25dB 低副瓣设计。     

一种低副瓣阵列天线指数幅度加权算法及仿真

在阵列天线的波束形成设计中,对波束的低副瓣设计提出了严格要求。提出了一种优化线阵列天线副瓣抑制的幅度加权的波束形成算法。通过此加权算法在小幅度展宽波束主瓣宽度的情况下,实现副瓣抑制高达30 d B的效果。并通过对多个不同单元数量的线阵列天线的方向图综合仿真计算,分析该算法参数对方向图的影响,该算法具有副瓣抑制效果好,简洁高效,易于工程实现等特点。     

低副瓣波导阵列天线工艺技术

本文介绍了合肥华档电子工程研究所最新研制的低副瓣波导阵列天线设计和加工技术概况。加工工艺是先进的ＣＡＤ／ＣＡＭ／ＣＡＴ一体化，保证了产品的高精度和高效率。     

一种新的低副瓣多波束形成方法

利用遗传算法优化一维线阵电流幅值的结果,结合单波束形成原理以及叠加原理最终成功实现了一维、二维、三维天线阵的超低副瓣多波束的形成问题。通过matlab编程仿真,结果显示设计效果非常好,波束方向,波束相对大小要求均能很好控制。该文对多波束天线的设计具有重要的指导作用。     

一种综合赋形波束天线阵的组合算法

提出一种新的组合优化方法。先通过遗传算法得到一个初步的优化结果,再用直接搜索算法进行二次优化,这样既突出了遗传算法全局寻优的特点,又避免了它在接近最优解时出现的小幅度随机波动。以低副瓣平方余割波束天线阵的综合为例,在主瓣达到要求的前提下,组合算法得到的天线阵方向图副瓣比直接搜索算法和遗传算法的副瓣低4dB以上。     

Optimum low sidelobe high crossover multiple beam antennas

Simultaneous multiple beam antennas (MBA's) with low sidelobe high crossover beams are considered. A simplified proof is presented which shows dissipative loss of typically -3 dB must be accepted. The optimum efficiency for the constrained fed MBA is shown to be achieved by placing attenuation in the aperture of a Butler matrix (BM) in accordance with the desired tapered aperture distribution. A combination of aperture attenuation and feed design, including the use of overlapping orthogonal feed distributions, is considered for lens type MBA's. The optimum efficiency is shown to be achieved with relatively simple feeds for a broad class of desired beam shapes.     

Design of a low sidelobe double difference beam for a circularaperture

A low-sidelobe double-difference beam is synthesized for a circular aperture in a manner similar to the synthesis of the circular Taylor sum beam and the circular Bayliss difference beam. The method proposed allows the designer to select a peak-to-sidelobe level ratio and an integer N which controls the shape of the close-in sidelobes. Such a beam finds use in main beam ECCM applications     

A low sidelobe asymmetric beam antenna for high altitude platform communications

In a communications network served by a high altitude platform, the antenna beams illuminating each cell require minimized sidelobe powers. Asymmetric beams are advantageous so that cell footprints remain circular. At millimeter wavelengths a lens antenna can have the desired properties. We have chosen a 6 km diameter cell at 32/spl deg/ elevation angle and shown how the required beam asymmetry can be implemented using an optimized polynomial for describing the lens profile. The measured average sidelobe level is below -42 dB.     

Shaped beam pattern synthesis with desired nulling level and minimum sidelobe level

For the anti-interference/denoise purpose, it usually requires minimizing the sidelobe level (SLL) of a wide-beam pattern with a desired low nulling level (NL) in the nulling region. To realize such an objective, the shaped-beam pattern synthesis (SBPS) is the most commonly used approach. However, since the SBPS problem focuses on synthesizing a predetermined beam shape, the minimum SLL via this approach cannot ensure to obtain the maximum power gain. Conversely, it cannot obtain the lowest SLL with a certain power gain requirement. Based on such consideration, this paper tries to further minimize SLL of a wide-beam pattern with a desired low NL nulling region, by solving the power gain pattern synthesis (PGPS) problem. The PGPS problem selects the array excitation by directly optimizing the power gain. Hence, it has the potential to reduce SLL, when achieving the equal mainlobe power gain constraint via SBPS. An iterative algorithm which converts the primal optimization problem into convex sub-problems is proposed, resulting in an effective problem-solving scheme. Numerical simulations demonstrate the proposed algorithm can obtain about 10-dB lower SLL than the existing algorithms.     

涡旋光束旁瓣抑制的研究进展

涡旋光束是一种具有螺旋型波前和光学轨道角动量的特殊光场,这种特性使其在光学微操纵、光学成像以及自由空间光通信等领域中具有广阔的应用前景.本文以螺旋相位板所产生的涡旋光束为基础,简要介绍了涡旋光束光强分布的特点,总结分析了目前几种涡旋光束旁瓣抑制方法的原理与特点,并就国内外的研究现状和应用前景进行了总结与展望.     

一种低旁瓣数字波束形成方法

线性约束最小方差准则(LCMV)在波束形成技术中得到了广泛的应用.但是,很多情况下,它会产生偏高旁瓣.本文基于多线性约束最小方差准则,提出了一种降低旁瓣的波束形成算法.该算法通过搜索技术寻找到已形成波束图的最高旁瓣点,建立对应方向矢量上的增益方程,将其添加到原来的LCMV准则约束条件中,然后利用多线性约束最小方差准则进行权值更新,实现旁瓣的降低.该算法不仅适用于均匀阵列,还适用于非均匀阵列,仿真结果表明了该算法的正确性和有效性.     

Low sidelobe precise beam aspect ratio scalar horns

A new design method for developing either linearly or circularly polarized low sidelobe corrugated sectoral horn antennas is described. These antennas may be designed to provide constant beam aspect ratios (BAR's) ranging from 2:1 to 5:1. Such performance is achieved over bandwidths of up to 21 percent for dual-linear polarization and 17 percent for circular polarization. Potential applications include use in communication satellite reflector systems where beam shaping, frequency reuse, or high adjacent beam isolation is required. Selecting aperture phase distribution rather than simply minimizing aperture phase error is the key to obtaining these results. Mechanical design and performance data are presented to facilitate fabrication of antennas that satisfy a wide range of performance requirements.     

基于旁瓣光束衍射反演的远场测量旁瓣波峰参数检测方法

针对强激光远场测量不能有效识别旁瓣光束任意方向各个旁瓣波峰参数的问题,提出了基于旁瓣光束衍射反演的远场测量旁瓣波峰参数的检测方法。对旁瓣光束图像按照选定的角度采样间隔进行量化,使用角度变换将二维旁瓣光束图像转化为全方向的一维旁瓣光束曲线集合,检测每一个角度的一维旁瓣光束曲线的各个旁瓣波峰参数,从而获得旁瓣光束任意方向各个旁瓣波峰的参数。主要优化措施为：(1)使用角度变换将二维旁瓣光束图像转化为全方向的一维旁瓣光束曲线集合;(2)检测每一个角度的一维旁瓣光束曲线的各个旁瓣波峰的参数,统计所有方向的各个旁瓣峰值,生成每个旁瓣波峰的极大值圆环;(3)统计每个旁瓣波峰极大值圆环的灰度均值,将各个旁瓣波峰极大值圆环的灰度均值与本底噪声进行比较,选择大于本底噪声1.5倍的最小波峰均值为整个旁瓣光束的最小可测旁瓣波峰信号。实验结果表明：该方法能够有效检测旁瓣光束任意方向各个旁瓣波峰的参数,任意方向上灰度极大值均值与理论值灰度极大值误差为0.477,5个波峰的极大值圆环半径均值与理论值半径之间误差小于1个像素。该方法提高了基于旁瓣光束衍射反演的远场测量的实验精度和可信度,为将来大科学装置强激光远场的精...     

A procedure for synthesizing a specified sidelobe topography usingan arbitrary array

A simple method to arrive at an optimum set of array excitations to achieve a specified radiation pattern is presented. An auxiliary function is formulated, based on the envelope of the required sidelobe structure and the array factor, in the sidelobe region. This function is minimized, subject to the main lobe constraints and the null steering constraints, to determine the excitations. An iterative procedure is used to generate the desired pattern, with the additional constraints like sidelobe level, symmetric excitation, and so on. The method has been successfully applied to synthesize linear arrays and circular arc arrays and to generate symmetric as well as asymmetric patterns     

Design considerations for low sidelobe microstrip arrays

The factors affecting the realizable sidelobe performance of microstrip arrays are discussed and quantified. These include excitation amplitude and phase accuracies, mutual coupling, diffraction effects, positioning errors, and errors due to imperfect element matching and feed network isolation. It is shown that low-sidelobe microstrip arrays require a very tight tolerance on the resonant frequencies of the elements, and the elimination of spurious radiation from the feed network. Cross-polarization and surface wave effects are discussed. An experimental 16-element microstrip array prototype incorporated these considerations into the design, and achieved a -35 dB relative sidelobe level