天线反射面单块面板精度检测浅析

介绍了天线反射面单块面板精度检测方法，详细分析了“水准仪＋高度尺”面板测量方法的检测精度，并对检测中的一些问题进行了讨论。     

面板算术平均值在天线反射面精度调整中的应用分析

天线面板检测后会得到两项数值，即算术平均值和均方根。均方根是衡量板精度的主要指标，算术平均值则是反射面精度调整的主要依据。本文将讨论面板算术平均值在天线反射面精度调整中的作用，给出二者之间的关系式。     

50m口径射电望远镜反射面精度分析

以50m口径射电望远镜为例,对影响反射面精度的各种误差做了分析,表述了整体误差与分项误差之间的关系。对结构变形的数值计算方法和曲面拟合方法做了说明,给出了计算结果,为望远镜的结构设计提供了指导。     

重力作用下天线反射面变形及其调整角度的确定

以结构力学分析为基础,根据最佳吻合抛物面的概念,应用矢量叠加原理推导出了大型天线反射面重力变形随俯仰角变化的数学表达式.针对天线表面精度在某仰角调整好而在另一仰角变差的问题,给出了求解反射面精度最佳调整角的优化计算方法.通过分析某工程12 m圆抛物面天线在多工况下的表面误差,及其与ANSYS软件计算结果的比较,证明了所推公式的正确性.数值计算结果表明:此方法能够得到合理的重力预调角.在工程上应用此方法设计和建造大型反射面天线,可提高反射表面的精度,改善天线系统的整体性能.     

一种大型反射面天线面板测试与调整方法及其应用

 针对大型抛物面天线反射面分块面板的特点,基于最佳吻合的概念,从机电耦合学科交叉的角度,研究了反射面分块面板的调整问题,推导出了靶标点与调整量之间的影响关系矩阵,给出了数值方法,研制了准实用软件.将程序软件应用于某实际天线中,收到了满意的结果.     

65m射电望远镜天线结构指向精度分析与设计

针对国内口径最大、精度最高的65 m射电望远镜天线,分析计算了其结构指向精度。介绍了轨道组合、枢轴组合和测角装置等关键部件的精度设计过程和结构误差,以及其他重力和环境因素引起的误差。通过结果分析、现场实测和长期工作,证明了天线结构设计指向精度的均方根误差达到11.8″,去掉系统误差,天线指向精度的均方根误差有望达到2″的精度。     

天线主反射面的几种测量方法介绍和分析

本文介绍了抛物面天线主反射面精度测量的几种方法，分析了这几种方法的测量原理、特点和应用情况，对经纬仪、激光跟踪仪、全站仪、激光雷达等方法进行了测量误差分析计算。     

加筋反射面板对天线结构精度贡献的分析

通过有限元分析计算能看出大型反射面板对天线结构精度有较大的影响，加筋反射面板的刚性可以降低天线结构重量和减小天线反射面的均方根值（ＲＭＳ）。     

上海65 m全可动天线结构变位疲劳作用分析

为掌握上海65 m天线结构俯仰变位的疲劳性能,首次针对全可动天线结构模拟其随机跟踪的工作方式,提出长期变位疲劳应力历程的计算方法,并应用其跟踪观测次数来表征其疲劳寿命;随后,基于简单抽样技术,采用实时雨流计数法对疲劳全寿命应力历程进行了简化;最终根据Miner线性累积损伤准则采用多次随机模拟的办法,分析了保证率为99%的俯仰轴疲劳寿命。结果表明:在设计基准期内,该天线结构俯仰变位疲劳寿命满足安全要求。     

An offset-fed reflector antenna with an axially symmetric main reflector

A design method for an offset-fed, dual reflector antenna (Cassegrain type or Gregorian type) system with an axisymmetric main reflector is presented. Geometrical optics (GO) and the geometrical theory of diffraction (GTD) are used to find the surface-current density on the main reflector. A modified Jacobi-Bessel series (JBS) method is used to find the far-field pattern for the physical optics (PO) integral. In the defocused mode of operation, a new technique is developed to find the reflection point on the subreflector corresponding to the defocused feed and a general field point on the main reflector. Two sample systems are designed.     

偏馈抛物面天线方向图外场测试分析

基于口径场法,提出了地基偏馈抛物面天线方向图的数值计算模型,分别给出了自由空间和镜面多径反射情况下的偏馈抛物面天线方向图,分析了测试距离对水平和垂直方向图的波瓣分布和增益的影响;同时分别仿真了固定测试距离情况下,偏馈抛物面天线镜面反射方向图随仰角和高度的变化规律.外场测试结果验证了仿真模型的正确性.该仿真模型能解释不同测试条件下,天线外场方向图的波瓣分布特点,对天线外场测试设计、性能评估和测试误差分析有一定的指导意义.     

Performance of a rectangular-waveguide-excited short backfire antenna employing a conical main reflector

The letter presents experimental results at X-band for a short backfire antenna employing a conical reflector, which is excited by a rectangular waveguide. It is shown that the use of a conical main reflector can lead to a compact antenna having a directive gain of 16.7?18.3 dB, sidelobe level below 13.8 dB and input VSWR better than 2.5 over a 20% bandwidth from 9?11 GHz.     

Realizable feed-element patterns for multibeam reflector antenna analysis

The radiation pattern of a feed element is approximately described by a simple function(cos theta)^{q}. For a given element spacing of the feed array, we give simple formulas for estimating the practical value ofqwhen the element is an open-ended rectangular waveguide, an open-ended circular waveguide, a pyramidal horn, or a cigar antenna.     

Fast integration techniques for reflector antenna pattern analysis

The letter describes the application of fast integration techniques, based on the FFT algorithm, to the evaluation of the far-field radiation integral for aperture plane, surface electric current and surface magnetic current theory. Results are presented comparing patterns derived by these three theoretical approaches.     

Shaped reflector antenna analysis using the Jacobi-Bessel series

The physical optics approximation is employed to derive the radiation integral for a doubly curved offset reflector antenna illuminated by an arbitrary source. A novel procedure is presented for expressing the radiation integral in terms of a summation of Fourier transforms of an "effective" aperture distribution which includes the effect of the curvature of the surface. The Jacobi-Bessel series is used to evaluate the Fourier transforms. The vector nature of the far-field pattern is studied by evaluating its three Cartesian components in a unified fashion. The rapid numerical evaluations of the expressions obtained are demonstrated via extensive test cases. In particular, the scattering characteristics of symmetric and offset parabolic, spherical, and shaped reflectors are studied in detail, and comparisons are made with other available data.     

赋形反射面多波束天线优化设计与分析

为了以较低的技术难度实现多个点波束对服务区的高增益、低旁瓣覆盖,提出了一种新型的赋形单口径多波束天线设计方法,通过对反射面赋形来解决传统单口径多波束天线旁瓣电平与波束宽度之间的矛盾.在对反射面优化过程中,将天线口径投影面内的相位分布作为优化变量,利用基于实数编码的遗传算法对其进行调整来获得满足要求的多波束覆盖.数值仿真结果表明:在保证增益大于40 dBi、旁瓣电平低于20 dBi的前提下,该设计能够将波束宽度拓宽为1°,可有效地提高了波束交叠增益,降低了旁瓣电平.     

低轨卫星测控系统三轴12 m反射面天线系统的结构设计

针对高码率低轨卫星测控的需求,给出了一种新型三轴12 m X/Ka频段天线的设计思路,通过优化反射面结构型式、材料选择、力学分析、减轻重量,提高天线反射体的精度;进行天线座架驱动链路设计和刚度设计,提高天线系统的谐振频率;通过优化伺服控制与伺服选型设计,提高伺服跟踪控制性能。基于Nastran/Patran有限元软件,对多种工况下的天线承载结构进行了刚度分析、强度分析、面型精度分析与结构固有频率等分析,结果表明典型仰角下的天线主面精度、承载能力及谐振频率均满足要求。依据有限元分析结果,采用高精度碳纤维天线反射体、高刚度A-E-T三轴天线座架、大动态伺服控制的设计方案,合理设计了12 m反射面天线的整体结构形式以及连接形式,并进行了天线实物的加工。所设计加工的12 m反射面天线满足高精度、高刚度、过顶跟踪的性能指标要求,对中大口径天线的设计具有一定的参考意义。     

Observation-point-dependent blocking shadows on a reflector antenna

The authors present efficient algorithms that can be incorporated in a physical-optics integration to account for migrating feed- and observation-point-dependent geometrical shadows caused by obstacles in the aperture of a reflector antenna with the feed under focused or scanned conditions. The expressions involve only addition and multiplication of simple low-order polynomials and hence do not introduce expensive overhead into the numerical integration. Obstacle shapes considered are disks, polygons, cylinders, and polyhedrons. Some appropriate diffraction corrections are presented which are compatible with the blocking algorithms