空间充气展开天线初步研究

结合3.5 m充气天线地面样机的研制,分析了柔性充气展开天线的结构形式和材料特性,对充气天线结构仿真分析、形面精度测量技术、电性能测试等进行了初步探讨。该地面样机形面均方根误差小于2.5 mm,成功完成了充气展开试验和折叠试验,并具有电性能,为进一步进行空间柔性可展天线研制积累了经验。     

天线时域测量技术及软件开发

本文首先介绍天线时域测量技术的原理和方法，然后介绍自行开发的以ＨＰ８７５３网络分析仪为基础的天线时域测量软件；利用无暗室条件下对天线方向图，增益等参量进行快速精确测量，大大提高测量精度和效率。     

一种机载双天线InSAR基线动态测量方法

机载双天线InSAR系统两个天线非刚性连接时,为保证高程测量精度和成像质量,必须对干涉基线进行动态精密的测量。该文研究了一种基于单相机和激光测距仪组合的动态基线测量方法,通过分别测量两个天线的中心位置和姿态,得到干涉基线长度和基线角。论文对该方法进行了原理性研究和地面验证实验,实验通过可精确控制轨迹的运动平台模拟天线运动,实验结果表明该方法在8 m摄影距离处位置测量精度优于0.2 mm,姿态角精度优于70,是动态测量干涉基线的有效方法。     

雷达天线的近场测量

一、引言高性能的雷达天线迫切要求发展高性能的天线测量技术。比主波束峰值低50dB的旁瓣电平和比毫弧度更高的指向精度正成为各种类型雷达天线的共同要求。普通的远场测量场常常不能适应上述天线的精确测量需要。木文主要叙述用近场测量技术对雷达天线方向图和增益的测量。新的测量技术不仅能测量天线的方向图和增益,而且能提高天线的测量精度和测量能力,降低测量费用,以及对天线作出诊断。表1列出了目前使用的雷达天线测量技术。     

多探头球面近场的校准

在多探头球面近场测试系统中,每个探头形成的测试通道间幅度和相位特性是存在差异的,各个通道不一致,如不进行修正,将会影响近场测试精度.介绍一种多探头天线测量系统的探头校准方法,属于无线通信技术领域,利用校准工具按照正确的步骤校准,可以实现多探头相位和幅度的自动化校准.本校准方法有效校准探头极化间相互影响造成的误差,提高校准的精度和可靠性,并且可以满足高性能天线的测量要求.     

纳米金属薄膜材料电磁参数测量方法

提出了一种基于波导法的纳米薄膜材料电磁参数测量的新方法,给出了该方法的基本原理.与常规波导测量方法相比,该方法根据纳米金属薄膜材料的特点,简化了求解算法,只需测出加载薄膜波导开路与短路时的复反射系数,即可求出薄膜的介电常数与导磁率,使测量过程简单高效并具有较高的精度.     

近场测量场地及应用

首先介绍了近场测量场地的发展历程,分析了移动通信天线未来的发展趋势及其对测量场地的要求,从测试功能、测试精度与测试效率三个维度讨论了近场测量场地在移动通信领域的应用,最后对近场测量场地暗室性能及探头性能检测方法作了简要介绍.     

天线方向图测量的角度误差及其消除方法

本文分析了卫星通信地球站入网验证测试中天线方向图测量的角度误差,提出了消除这种误差的方法。所用的计算机程序可以大大提高测量精度,并可减轻操作人员的工作强度。该方法也可用于一般的天线测量。     

基于哈特曼原理的薄膜应力在线测量系统

介绍了一种基于哈特曼传感器的薄膜应力在线检测系统.哈特曼透镜阵列将待测量表面划分成若干小区域,通过测量每个小区域成像光斑的相对位置变化来获得整个测量表面的变形量,将测得的变形量代入到薄膜应力与基板表面变形的关系式中,求得薄膜应力.通过对影响光斑质心探测精度的各种因素进行分析,提出使用加阈值的一阶矩法,精确计算光斑质心,结合高灵敏度的CMOS探测器,使系统的面形测量精度达到15.7 nm,应力测量灵敏度优于3.3 MPa,实现了薄膜应力测量的高灵敏度与在线测量的统一.最后通过对TiO2,SiO2单层膜的在线测量,验证了系统的灵敏度与稳定性,能够完全满足薄膜应力分析的需要.     

毫米波天线测量系统及测量精度分析

随着毫米波天线应用环境和设计复杂程度的不断增加,对毫米波天线的测量也提出了更高的要求,为适应宽频 带毫米波天线快速测量的需求,本文基于R&S 公司ZVK 矢量网络分析仪,研究了毫米波扫频紧缩场测量系统的特性, 针对影响其测量精度的主要因素进行了详细的分析讨论,阐述了系统改进主要方向,并给出了测量实例。     

A novel antenna concept for future solar sails: application of Fresnel antennas

Recent studies have shown that interplanetary missions may be made possible using inflatable solar sails that employ solar-flux power, providing thrust for spacecraft while reducing onboard fuel requirements. These sails require a large surface area (i.e., 100 m in diameter) to capture enough solar flux for spacecraft navigation. In this paper, a novel communication antenna concept is proposed for future solar-sail missions, taking advantage of the large sail surface area via application of Fresnel-zone (FZ) antennas. This study focuses on utilizing a design/analysis methodology using physical optics (PO) and method of moments (MoM) for Fresnel-type antennas applicable to the solar-sail missions. Extensive parametric studies of Fresnel-zone antenna radiation characteristics have been performed, and the analytical methodologies were verified using a series of measurements. Fresnel-zone antenna gain is studied under different antenna configurations. Furthermore, a Fresnel-zone antenna under surface deformation is investigated to characterize Fresnel-zone antenna performance in the reflective mode. In addition, a new bandwidth-enhancement technique is introduced for Fresnel-zone antennas, to accommodate the dual-band operation ( X band uplink and downlink) of the antenna for the deep space network (DSN).     

一种高频电大尺寸天线测试的新方法

文章提出一种简单可行的高频电大尺寸天线辐射测量新方法.该方法基于天线形面光学精密测量,将形面分为多个区域,每个区域带入实际光学测试采样点数据,采用电磁场数值计算得到天线的辐射方向图.光学测试系统提供了足够高的测试精度可以满足微波、毫米波甚至太赫兹等频段天线的测试要求.该方法还可以解决超大型可展开天线测试以及模拟星载环境实验条件下天线辐射测试难题.     

Recent advances in ‘in-orbit testing’ of communications satellites

After a successful launch of a new communications satellite, it is essential to test the communications subsystem while the spacecraft is in orbit so as to compare with prelaunch data in order to ensure that no impairment has resulted from the stress of the launch and to verify that the spacecraft payload is compliant with the specifications sought. The thrust of in-orbit test technology has stemmed from the fact that the spacecraft has to be operational very quickly while not sacrificing the number of tests that have to be performed and increasing their measurement accuracies. Thus, in order to respond favourably to the cited criteria, microwave measurement techniques with more powerful computers and software technology have been used to automate the measurements. The paper is geared to the history, design, implementation and operation of EUTELSAT's in-orbit test (IOT) facilities, and mostly reflects technological advances in communications satellite payload testing. The paper will first detail the hardware/software novel concepts of the measurement environment. Then new measurements are summarized. New spacecraft antenna mapping procedures are detailed both in measurement and spacecraft attitude aspects.     

一种新型低剖面、宽频带全向天线设计

设计了一种改进结构的嵌入盘形天线,该天线具有低剖面、宽频带及全向的特点,并要求工作时最大辐射方向是45°。通过对嵌入盘形天线进行刻缝和加导电柱等结构上的改进后,可以在降低天线尺寸的前提下实现天线的低剖面、宽频带以及较大的水平增益。天线中心频率为3.0GHz,剖面高度远小于中心频率波长。在2.5～4.0GHz频带内,驻波比小于2,并且,水平方向增益可达-2dB。用AnsoftHFSS软件进行仿真计算,并对实际天线进行了测试。测试结果与仿真结果有很好的一致性,满足设计要求。     

Satellite system measurements

This paper describes the measurement techniques employed to test the elements of a communications satellite system. Techniques for measuring the gain-to-noise-temperature ratio (G/T) of an earth station antenna are presented. The measurement of earth station polarization characteristics is discussed extensively in terms of the new requirement for frequency reuse on orthogonal polarizations. Methods for in-orbit measurement of spacecraft performance including antenna characteristics are included, as well as some typical experimental results.     

基于超表面的低剖面高增益圆极化天线

提出了一种基于缝隙耦合超材料表面的低剖面圆极化高增益天线,该天线由一个超材料表面和一个微带缝隙天线紧贴着组成. 通过改变超表面切角的大小来产生圆极化波,同时还可以提高天线增益和拓宽阻抗带宽. 为了验证仿真结果,制作和测量了一个大小为1λ×1λ×0.067λ(在10 GHz处)的样本天线,仿真和测量结果显示出良好的一致性. 结果表明,在整个工作带宽内天线的增益均在7.5 dB以上,最大增益达到10.5 dB,比普通缝隙天线提高了5.3 dB,阻抗带宽(S₁₁ < ?10 dB)为27.4%,轴比带宽(AR < 3 dB)达到12.3%. 因此,该天线能同时满足低剖面、圆极化、高增益等多种性能的要求,可以应用于许多领域.     

Testing of the MESSENGER spacecraft phased-array antenna

The MESSENGER spacecraft, designed to orbit the planet Mercury, uses the first electronically scanned phased-array antenna for a deep-space telecommunication application. Two lightweight phased arrays, mounted on opposite sides of the spacecraft, provide the high-gain downlink coverage. Techniques for measurement of the phased-array antenna system include ambient temperature measurements in a compact antenna range, thermal vacuum testing, and spacecraft-level testing. There have been two novel developments in the characterization of the phased-array system. The first is a "gain envelope" response, which is a measurement of the gain of the array at the intended scan angle as the array is electrically scanned in 1/spl deg/ increments. This response was produced through a combination of hardware and test software to synchronize the gain measurement with the mechanical and electrical scanning. The second is a phase-steering verification test that utilizes couplers in each steered element in conjunction with previously measured element patterns to confirm that the antenna beam is steered property. This method allows functional verification of the phased-array system while radiating into an RF-absorber-lined hat during spacecraft-level tests.     

Far-field patterns of spaceborne antennas from plane-polar near-field measurements

Certain unique features of a recently constructed plane-polar near-field measurement facility for determining the far-field patterns of large and fragile spaceborne antennas are described. In this facility, the horizontally positioned antenna rotates about its axis while the measuring probe is advanced incrementally in a fixed radial direction. The near-field measured data is then processed using a Jacobi-Bessel expansion to obtain the antenna far fields. A summary of the measurement and computational steps is given. Comparisons between the outdoor far-field measurements and the constructed far-field patterns from the near-field measured data are provided for different antenna sizes and frequencies. Application of the substitution method for the absolute gain measurement is discussed. In particular, results are shown for the 4.8-m mesh-deployable high-gain antenna of the Galileo spacecraft which has the mission of orbiting Jupiter in 1988.     

RF characterization of an inflatable parabolic torus reflectorantenna for space-borne applications

Space-borne satellite applications provide a vast array of services extending from global connectivity to Earth observation systems. The soil moisture radiation mission is a proposed space-borne passive microwave system complementary to the existing Earth observing system operating at low microwave frequencies and requiring an antenna with multibeam, high-beam efficiency, and dual polarization capabilities. To achieve both the large reflector size and the multibeam pattern at the operational frequencies an innovative multibeam reflector antenna design was needed. The advances in inflatable antenna technology has been proposed to overcome the launch vehicle size and weight restrictions. This paper describes a novel offset parabolic torus reflector antenna design that produces the desired multibeam pattern and is compatible with the inflatable antenna technology. Using the system requirements of this mission as an example, the design process for an inflatable parabolic torus reflector antenna is outlined, the development of suitable distortion models is given, and representative RF characteristics are presented. These RF characteristics include far-field patterns, beam contour patterns, beam efficiency, and other key performance parameters. The development of an advanced analytical modeling/numerical tool in support of the design effort is also detailed     

空间大口径薄膜反射聚能系统

能源是航天器能够正常工作的基本保证,太阳能、引力能、真空能等太空即时补给能源是航天器供能的焦点。提出基于大口径薄膜反射的空间聚能系统的研究方案,利用充气式囊状薄膜反射镜结构聚焦太阳能,在焦斑处结合热电转换技术,实现了太阳能的汇集和能量的热电转换,并应用仿真软件模拟得到了不同焦距值的反射面聚焦效果的对比数据,验证了方案的可行性。所提出的以光、热、电三种能量形式为飞行器供能的设想为空间飞行器能源系统的设计提供了新思路和新技术。