环绕式微带共形天线辐射特性的研究

基于腔模理论和等效原理推导出环绕式微带共形天线远区场的表达式。根据该表达式算得的TM_(01)模天线方向图在相对介电常数较小时与文献〔3〕的结果相吻合。同时还研完了圆柱半径对天线方向图的影响。     

箭上电磁环境检测接收天线研究

针对目前运载火箭舱内电磁环境愈发复杂且没有有效的测量手段的问题,研制了一种超宽带无源小型化接收天线。该天线采用多个整形单极子的方式拓展带宽并达到小型化目的。接收天线的测量频率范围覆盖500 MHz~6 GHz,尺寸约为60 mm×60 mm×100 mm。通过加入低噪声放大器,使可测量的最低电场强度不高于1 mV/m。由于多个整形极子天线存在相互干扰情况,因此接收天线在频率响应上与理论值存在差异,该差异可以通过校准进行消除。通过数值仿真和样机试验测试,该天线系统的测量能力良好,符合设计预期。将该接收天线应用装载在运载火箭舱内,可以对目前已知的箭上无线系统发射频段进行有效测量,对飞行过程中箭上真实电磁环境的确认、舱内电磁兼容设计、箭地无线链路设计具有重要作用。     

电机电流分析法在测控天线传动系统故障诊断中的应用

分析了天线传动系统影响电机电流特性的因素，提出了天线正常跟踪卫星以及电机启动、制动时的电流特性标准，利用电机电流分析法对测控天线传动系统的周期性故障、阻尼增大故障以及系统级故障进行定位判断。结果表明，电机电流分析法可以作为天线传动系统故障诊断的一种有效手段。     

Impact of DORIS ground antennas environment on their radio signal quality

Among the factors which may disrupt the DORIS measurements quality, the ground antennas environment is of high importance. For a set of 15 selected DORIS beacon, the differences between the effective and theoretical power received on-board the satellites (SPOT-5 and Envisat) have been analyzed in terms of spatial direction around the antenna. Such antenna maps have also been established regarding the Doppler residuals of the least-square precise orbit adjustment. Thanks to 360° views from the antennas and aerial views of the sites, the impact of the signal obstructions (trees, roofs, antennas …) on power attenuation and Doppler residuals is discussed. Depending on the nature of the obstructed object, the attenuation level can reach more than 5 dB, and the residual RMS of the orbit adjustment may be doubled from the nominal value, reaching 1 mm/s locally. The nature of the ground at the foot of the antennas has been correlated to DORIS signal quality at high elevation: reflections on flat surfaces (e.g. roofs) affect the signal more significantly than reflections on natural ground (e.g. soil). In particular, a modeling of the multipath phenomenon affecting Fairbanks site has been established and fits remarkably with the observations. Finally, an evaluation of the direct impact of obstructing objects on the orbit has also been performed. The example of a scaffolding at Kauai site displays a few millimeters error in the along-track position of the satellite.     

航天飞行器典型高温透波结构热匹配性能分析

针对一种航天飞行器典型天线窗类高温透波结构及其安装形式,通过Abaqus有限元仿真分析方法对其热匹配特性进行了研究。研究表明:天线窗结构热匹配产生的热应力主要与金属壳体受热膨胀有关,石英纤维增强二氧化硅天线窗具有更优越的热匹配性能,天线窗直径越小,厚度尺寸越大,热应力越小,热匹配性能越好。该项研究为典型天线窗类高温透波结构在航天飞行器上的应用提供了参考。     

Various methods of calibration of the STEREO/WAVES antennas

On October 25th, 2006, NASA’s two STEREO spacecraft were launched which are designed to increase our knowledge of the physics of the solar system. On board they carry a sophisticated radio experiment, called S/WAVES. The key technology, used by S/WAVES is the direction finding capability in addition to the use of two spacecraft which makes it possible to triangulate radio sources. Direction finding requires the reception properties of the antennas to be known very accurately. We applied several different methods to calibrate the S/WAVES antennas. In this paper the methods are described and compared and the results are presented and discussed with respect to advantages and disadvantages of the different methods.     

赋形的哥利高里馈源

本文描述的赋形馈源,由喇叭、椭球副反射器及将它们连接起来的介质体构成。通过赋形,该馈源可使反射面天线的主反射面口面得到预定的振幅和相位分布。文中叙述了赋形馈源的物理原理,推导了赋形方程,从而得到了赋形馈源的工程设计方法。应用该赋形馈源,可以免去一般反射面天线的馈源支撑,并保持抛物面主反射器的形状不变。     

消旋天线机构轴承摩擦力矩研究

叙述了在大气条件下,不同轴向载荷,转速,滚珠数和润滑剂对C7046112轴承摩擦力矩的影响。试验结果表明:轴承轴向载荷与摩擦力矩关系并非单调上升函数,而是一个具有极大值与极小值的周期函数,并对试验结果进行了讨论。文内对进行试验的DZS-1气浮加载轴承动态特性试验设备也进行了介绍。     

宽带双极化天线测量探头的设计与仿真

天线测量探头的性能对提升天线平面近场测量效率、最终测量结果的精度具有重要意义。针对平面近场测量的需要，应用反向四脊和差分馈电技术，设计了宽带双极化天线测量探头。对测量探头模型进行仿真，分析了带宽、方向图、隔离度和交叉极化辨识度等探头性能，确定了高隔离度、高极化纯度的宽带双极化天线测量探头的最优设计，获得了更高精度和效率的天线测量。     

Performance verification of Lunar Regolith Penetrating Array Radar of Chang’E-5 mission

Lunar Regolith Penetrating Array Radar (LRPR) is one main payload of the Lander for Chinese Chang’E-5 (CE-5) mission. It is used to support the drilling and sampling device and to detect lunar regolith thickness and structure of the landing site. LRPR will only work in situ under static status, so the antenna array is employed. Since the antenna array is about 90?cm high from the ground, the layout is irregular, and the metal structure of the lander seriously interferes with LRPR, these factors make it very difficult to reconstruct the image of the drilling area, so the performance verification must be carried out. We propose a set of methods to process LRPR’s data and reconstruct image. The verification experiments demonstrate that these methods are suitable for LRPR, the thickness and structure of the lunar regolith from zero to two meters can be clearly mapped, the vertical resolution is a few centimeters, and the electromagnetic properties of the subsurface can be estimated. Therefore, the performance of LRPR meets the requirements, and LRPR can successfully support drilling and sampling.