X波段32元高增益阵列天线设计与仿真

本文研究了一种X波段32元高增益带状线天线阵的设计方法。阵元排列采用泰勒分布实现低副瓣。通过优化带状线对称振子结构,展宽了阵列天线阻抗带宽。讨论了天线单元结构尺寸与天线阵列带宽之间的关系,介绍了带状线天线阵馈电网络以及带状线转微带接头的工程实现途径。仿真计算结果表明,天线阵列在8%的相对带宽内电压驻波比小于1.4,增益大于20dB,并具有良好的阵列方向图。     

基于遗传算法与粒子群优化法的机载合成孔径雷达天线赋形波束综合

采用了遗传算法和粒子群优化法两种现代进化算法对赋形波束天线进行了综合,得到了很好的结果,并比较了两种算法的优缺点.首先通过对宽测绘带的机载合成孔径雷达距离向回波特性的分析,给出了天线距离向赋形辐射方向图表达式.接着利用两种现代优化算法结合谢昆若夫法对天线阵分别进行综合,得到了近似相等的天线各单元激励幅度和相位.然后选择5个单元激励并利用微带贴片天线阵列实现了赋形波束方向图,实验结果和理论优化结果基本吻合,从而证明了这两种现代进化算法对赋形天线方向图综合方法的有效性.     

集合线对对数周期偶极子天线的影响

主要研究了对数周期偶极子天线．基于Pocklington积分方程和全域基函数，采用矩量法结合网络理论建立了天线算法模型；使用该模型计算了在天线阵和集合线共同作用下天线的辐射方向图，得出了集合线在不同频段上对天线辐射性能的影响，并通过截短延长线长度改善了天线低频段的辐射特性，增强了天线轴向方向性．     

一种新型的OFDM智能天线

根据自适应天线阵列理论，结合给定的参考波束的误差，引入虚拟干扰的概念，对目标波束图形状进行调整，提出一种新的可以应用于任意类型天线阵列的波束综舍算法．应用提出的新算法，在主辩和旁瓣位置都可以对波束进行有效的调节．最终获得阵列的最优权矢量，能够最小化目标波束图与参考波束图间的差异．理论分析与仿真结果表明，与现有的同类算法相比，该算法能更有效地获得与参考波束基本相符的波束．应用于OFDM智能天线系统时，对不同子载波频率上信号进行单独处理，利用该算法进行波束综合，能够在整个有效频段，使所有子载波上获得基本一致的阵列输出．     

多约束线性非均匀阵列天线的合成

为了提高线性非均匀阵列天线的优化效果,降低阵列天线设计的复杂性,本文提出了一种改进的蝙蝠算法来实现更低的峰值旁瓣电平(PSLL).改进的蝙蝠算法在阵列孔径约束和阵元上下界限的限制条件下,优化每个阵元位置来获得方向图峰值电平最低,实现全阵列最佳的阵元位置.本文分别对18个阵元和32个阵元阵列天线数值仿真,仿真结果达到了-20.081 dB和-22.656 dB.从而验证了提出方法的有效性和稳定性,并且实现了更高的优化效率.     

天线柱面近场测量的散射源误差抑制方法研究

根据柱面波近远场变换基本原理,引出柱面波模系数与辐射源空间位置的特定约束关系,提出一种先将柱面波谱数据进行滤波处理,然后进行波谱远场变换,最终得到抑制散射误差后的远场方向图的方法。随后通过构建阵列天线模型,对抑制效果进行仿真分析。结果表明:该方法在第Ⅰ副瓣位置可改善2d B,120°范围内方向图与理想结果较为吻合,能有效抑制散射误差对远场方向图产生的影响。     

圆极化高温超导微带天线阵

在0．62mm厚的MgO衬底上,设计和制造了一个用于直接广播卫星（DBS）系统的圆极化和单一馈电网络的四单元高温超导微带天线阵,中心频率为12．2GHz。为了比较,一个天线采用金膜制造,另一个采用超导薄膜钇钡铜氧（YBCO）制造。为了提高圆极化阵的轴比特性,运用连续旋转技术,分别在室温和液氮温度下测试效率、方向性、回波损耗和带宽。采用超导薄膜钇钡铜氧（YBCO）制造的阵表现出很好的圆极化特性,在77K时的增益比室温时的金膜天线阵大1．64dB。在谐振频率12．24GHz时回馈损耗为-30．6dB,总有效带宽约为3．52％,表明当高温超导体用于微带天线阵时,能提高天线阵的效率。     

大型数字阵列天线的软件化测试

数字阵列由于其众多的优点使其在雷达、通讯领域都得到广泛的应用。但是阵列天线各种系统的误差,严重影响系统的性能。所以,阵列天线的校正测试十分重要。随着大型天线阵面的发展,成千上万的天线单元增大阵面测试的复杂度和工作量。而专门的测试系统一般开发成本极高,而且不具备通用性要求。虚拟仪器系统开发平台LabVIEW结合通用的数据采集仪器,通过软化设计,编制具有友好人机交互界面的数据采集和监视VI(虚拟仪器),实现阵列天线测试过程中的通道监视、数据采集,最终完成数字天线阵列的测试工作。     

磁偶极子天线方向性的边界元解法

应用边界元法对磁偶极子天线的辐射方向性进行解算，比较数值结果进一步获得传播距离与天线尺度的关系对方向性的影响，有助于进行磁偶极子天线及其电磁探测系统近程工作性能的分析与优化设计。     

一种基于的遣传算法的微波测量分析方法

论述了遗传算法在微波测量分析中的应用,首先简要介绍了应用遗传算法处理微波数据信号．然后在微波电路的分析设计中,设计了一种较好的遗传算法多目标优化方法对电路进行全局优化．使整个系统在电路设计等关键的衡量指标同时达到最优．文章对双波段、六单元接换阵列智能天线运用遗传算法进行优化设计,在900MHz和1900MHz两个频段上-10dB带宽分别达到和,天线辐射方向上的最大增益为．最小增益为,并且得到了天线阵列中每个变量的灵敏度分析．通过与文献的比较,结果证明遗传算法的应用可以显著的提高天线的性能．     

Steerable reflect-array antenna formed by loaded electric dipoles

Technical Physics Letters - A reflect-array antenna with simple design, low cost, and electronically controlled directivity pattern for centimeter wavelength range is proposed. The antenna is based...     

Directional field enhancement of dielectric nano optical disc antenna arrays

This paper presents a discussion on the directive field enhancement of dielectric disc antenna arrays in optical band. The property of dielectric material is addressed, and field modes in a cylindrical resonator are discussed. It is identified that the fundamental mode of HE_11δ generates the far field with a higher directivity than other modes. More effective field enhancement in the radiation direction could be achieved by using multiple-disc antenna arrays. Simulation examples indicate that the directivity of a disc antenna array varies with the disc spacing. The maximum directivity is observed when the disc spacing is approximately equal to the half of the vacuum wavelength. The maximum directivity can be improved significantly when the disc number is increased.     

Phase distortions in an anisotropic Luneberg lens

The field phase distribution over the aperture of a Luneberg lens composed of radial dielectric rods is approximately calculated, and the influence of this distribution on the directivity pattern of this antenna is estimated. The results of calculations of the difference of electrical pathlengths for the angles ϕ=0 and 90° for Δε=0.2 are presented.     

Directional emission of surface-enhanced Raman scattering based on a planar-film plasmonic antenna

A planar-film plasmonic antenna for surface-enhanced Raman scattering (SERS) with good emission directivity (divergence angle < 3°) was realized on a Kretschmann prism configuration with Raman-active analytes as emitters. The simulated results of finite-difference time-domain method show the emission efficiency, the directivity and the gain of the planar-film antenna were expected to be 50%, 300 and 22 dB, respectively. Angle-resolved spectroscopy was used to characterize its properties in SERS. The experimental results show that the SERS signal of analytes was remarkably enhanced when a laser excited this planar-film plasmonic antenna at the resonance angle. Meanwhile, the radiation of SERS was concentrated in a small region in space. The planar-film antenna with high gain coefficient can be a promising light harvesting and emitting device. The good emission directivity allows high collection efficiency. This advantage opens up interesting prospects in the applications for plasmon-enhanced spectroscopy and single-phonon detections.     

单台阶同心圆盘辐射声场的指向性计算

作为向空气中辐射的声辐射器,弯振阶梯薄盘或矩形板在工业上有很多应用。由于计算的复杂性,以前的文献对阶梯圆盘的声场指向性未作研究。利用点声源组合的方法（Rayleigh积分）,计算了边界自由的弯振阶梯圆盘辐射声场的指向性,与弯曲振动的圆盘相比,阶梯圆盘的声场指向性得到了明显改善,理论计算结果与Gallego的实际测试图案相吻合。计算为这类辐射器的高效应用、优化设计提供了理论依据。     

Performance profile comparison of the quasi-lumped element resonator antenna

The performance profile comparison of the quasi-lumped element resonator antenna is presented. The specific advantages of this antenna are investigated by comparing it to the standard long wire antenna approach, and, in particular, also to the many available differently loaded wire antenna approaches, which are also optimized for maximal radiation efficiency and directivity for example, the capacitively loaded long wire antenna and the planar H-shaped elements loaded transmission line design. It was noted that the quasi-lumped element resonator antenna formed by small interdigital capacitors and line inductors proved to be compact in size with an aperture size of 5.8 × 5.6 mm² and better directional characteristics.     

Excitation matching procedure for sub-arrayed monopulse arrays with maximum directivity

The maximisation of the directivity of compromise difference patterns in sub-arrayed monopulse linear array antennas with an optimum sum mode is addressed by means of a two-stage excitation matching procedure. The knowledge of the independently optimum difference excitations, which provide maximum directivity, is exploited with an efficient matching technique based on the contiguous partition method. Simple and reliable compromise solutions, characterised by reduced complexity as well as easier manufacture of antennas, are synthesised to assess the effectiveness of the proposed method also in comparison with state-of-the-art methods devoted to directivity maximisation.     

小型化线列阵研究

介绍了一种小型化线列阵,阵结构与常规线列阵最大的不同在于阵元间距小于四分之一波长。通过理论分析和仿真计算优化了各阵元的最佳权系数,获得了良好的指向性,得到了实验的证明。小型化线列阵的指向性图具有四大特点：①单向性：仅在半空间出现一个轴对称的主波束,无栅瓣和次瓣。②端射特性：主波束出现在线阵的轴射方向。③超指向性：在阵的尺寸远小于二分之一波长条件下不仅可以获得良好的指向性图,并且波束宽度随阵元间距的减小而减小。④恒定束宽特性：在阵元间距小于八分之一波长条件下,波束宽度随频率变化非常平缓。这种小型化基阵也可用于大型基阵如拖曳阵和展开式体积阵的子基阵,进行低频宽带信号的检测。     

Benthic hydroacoustic antennas in three-dimensional nonuniform currents: Computation and optimization

A method is proposed for computing the configuration, tensile stress and directivity pattern of a linear hydroacoustic antenna, situated in a 3-dimensional nonuniform current. Consideration is given to the possibility of optimizing the hydromechanical parameters of the antenna, in order to improve their spatial stability under actual ocean conditions. Translated from Izmeritel'naya Tekhnika, No. 7, pp. 58–61, July, 1996.     

Fabrication and characterization of a three-dimensional feed-horn infrared antenna for an infrared detector

A three-dimensional feed-horn antenna for the 10-microm-wavelength infrared region has been suggested, characterized, and fabricated. It is applied to an infrared detector for efficient collection of infrared radiation and to reduce background noise. The optimum size of the horn antenna was designed for maximum antenna directivity. The three-dimensional feed-horn antenna mold was fabricated by rotating and tilting illumination, whereas the antenna plate was acquired through electroplating. Antenna characteristics were measured by coupling of the antenna with a microbolometer. Measurement results show that the directivity of the antenna is 16.1 dB and the background noise is reduced by a factor of approximately 2 compared with an open-structure infrared detector.