高功率微波极化方式与入射方向对微带线耦合特性影响分析

针对高功率微波（HPM）耦合效应分析需求,采用时域多分辨分析法（MRTD）模型,给出了微带线端口电压和电流方程,验证了模型的适用性。基于MRTD,仿真分析了HPM作为入射波时其极化方式、入射方向对微带线电磁耦合特性的影响。结果显示：垂直线极化波和平行线极化波耦合系数峰值出现在不同的频率,且峰值相差约15 dB,采用圆极化波时耦合系数最大;入射方向变化时,耦合系数以水平入射最小,垂直入射时最大,高频段微带线边缘有绕射现象产生。该分析采用了分析计算电大尺寸HPM耦合效应的MRTD数学模型,提高了HPM与复杂结构的耦合计算效率。     

中继卫星S/Ka双频地面站天线共用跟踪接收机

论述了Ka频段圆波导TE11和TE21模自跟踪体制和S频段正十字排列四喇叭自跟踪体制共用两信道自跟踪接收机问题.导出了来波及地面天线S频段和、差信道极化特性引起的角误差电压的交叉耦合系数公式.还可以进一步使S/Ka两个频段共用一套能跟踪（直接序列）扩频信号源的伪单脉冲（单信道单脉冲）自跟踪接收机.     

基于宽带滤波巴伦的端射滤波天线

端射天线是一种辐射方向与阵轴的方向一致的天线,因为其具有良好的方向图特性,通常应用在军用雷达探测系统用来解决“盲区”问题。端射天线和滤波器之间由于匹配电路的存在导致系统尺寸较大、损耗增加。将端射天线和滤波器作为整体器件设计成端射滤波天线,端射滤波天线不仅具有辐射、阻抗匹配、滤波和平衡转换功能,而且可以减小电路尺寸,使系统结构更加紧凑。文章通过采用闭合环谐振器设计一款结构紧凑的多层宽带滤波巴伦,并将宽带滤波巴伦和准八木天线进行集成,设计出了一款中心频率 2.5 GHz的端射滤波天线。该滤波天线具有频率带宽较宽、频率选择性高、带外抑制好、结构紧凑等特点。     

X及Ku波段宽带极化转换超表面设计及RCS缩减应用

针对反高分辨率雷达探测的电磁隐身问题,本文设计了一种作用于X和Ku波段的宽带反射型极化转换超表面,能够在6.5～8GHz范围内实现85%以上的极化转换效率,在8～20GHz范围内实现90%以上的极化转换效率,极化转换效率在85%以上的相对带宽达到了101%,且超表面剖面较低,整体厚度小于3.6mm,并将其自身和镜像单元设计成了方形式和三角式棋盘阵列排布结构。在x极化和y极化电磁波垂直入射下,与同等大小金属相比,两种棋盘式阵列排布结构的雷达截面积（RCS）缩减效果明显,且具有极化不敏感的特性,其中方形式棋盘结构RCS缩减峰值达到了22.91dB,RCS减缩均值达到了11.73dB;三角式棋盘结构RCS缩减峰值达到了36.07dB,RCS减缩均值达到了12.29dB,起到了大幅度降低单站RCS提升电磁隐身性能的作用。     

多模伪单脉冲自跟踪系统的性能限制

给出了大信噪比和小信噪比情况下圆波导TE11和TE21模伪单脉冲系统合成信号包络的表达式。指出在小信噪比情况下,将不能从合成信号的包络解调出角误差电压。给出了大信噪比情况下热噪声引入的跟踪误差。     

极化角对跟踪接收机相位影响分析

根据卫星通信中遇到的极化问题及其对移动地面站的影响,针对不同极化卫星间的差异,从电磁场理论中极化的定义和分类出发,给出不同极化电磁波电场信号表示方法,以某型移动卫通站天线馈源结构为例,介绍了不同状态下极化工作方式和线极化方式中线极化面调整的机理,然后结合单通道单脉冲跟踪接收机工作原理,对天线跟踪水平极化信标时线极化角与跟踪接收机相位间的关系进行了详细分析,为解决实际应用中遇到的跟踪接收机相位漂移问题提供了技术依据。     

副反射面调整模型及工程实现方法

针对大型反射面天线重力变形导致天线性能恶化的问题,提出了用副反射面实时调整减小重力变形影响的方法,分析了副反射面位置平移和旋转对天线增益和指向的影响,并建立了副反射面姿态随天线仰角角度变化的数学模型。用数字摄影测量得到了一组35m天线在不同仰角时的主反射面变形数据,并进行最佳吻合,从而得到一组副反射面最佳位置坐标,再与测量的对应仰角的副反射面在重力作用下的自身位移数据叠加,可以得到一组最终副反射面调整数据。将其代入数学模型,用最小二乘法进行最佳拟合,求出数学模型系数,再将该模型用于副反射面实时调整系统,则可减小重力变形对天线性能的影响。仿真结果表明,采用该模型对副反射面位置实时调整后,35m天线在X和Ka频段的天线增益分别提高了约0.52dB和1.95dB。     

深空大规模天线组阵布局设计

针对深空测控通信背景下大规模组阵的天线布局优化问题,给出了优化目标(即单元波束内合成波束附近的旁瓣最小化)以及优化边界条件(包括天线数、天线口径、工作频段、最小间距和最大布局范围等),并在此基础上建立了优化模型,理论分析表明,布局优化后的归一化旁瓣峰值比布局随机化的归一化旁瓣峰值低lnN/N(N为天线数)。最后基于梯度优化算法给出具体的优化流程并进行了仿真,仿真结果表明,在给出的优化边界条件下,优化后的合成波束方向图旁瓣峰值降到约-10dB,与理论分析结果基本一致。     

出口宽高比对S形二元收敛喷管雷达散射截面的影响

在S形二元收敛喷管进出口面积、偏心距、面积变化规律及中心线变化规律不变的条件下,采用自适应超椭圆方法设计不同出口宽高比的S形二元收敛喷管.基于迭代物理光学法与等效边缘电磁流法自主开发计算腔体部件雷达散射截面（RCS）的程序;然后通过文献中的实验数据验证了计算程序的准确性和可靠性.通过计算程序分别分析了水平、垂直两种极化方式下不同S形二元收敛喷管的边缘绕射场与总散射场的电磁散射特性.结果表明:在水平、垂直两种极化方式下,喷管出口宽高比的变化对S形二元收敛喷管边缘绕射场的RCS影响较小,不同出口宽高比的S形二元收敛喷管边缘绕射场的RCS相差不超过4dB.喷管出口宽高比的变化对总散射场的RCS影响较大;正探测角时,宽高比为1.5时,在大部分探测角范围内总散射场有较低的RCS;负探测角时,宽高比为3.5时有较低的RCS.      

反射面天线的双站雷达截面

 本文导出了任意旋转反射器天线在任意双站角的散射场和雷达截面(RCS),其中反射场由几何光学法(GO)求得,绕射场则利用基于物理绕射理论(PTD)与等效线电流辐射积分公式导出的等效电磁流法求得。分别计算了轴向入射和偏轴向入射时在任意散射方向上水平极化与垂直极化两种情况下的双站RCS,并给出了这些结果的立体图形式。方法简化为单站情况时的计算结果与实验值大致相符。     

K-Band Tracking System for Domestic Satellite Communication System

System design and operational results of a tracking system for a K-band Earth station antenna with a diameter of 11.5 m are discussed. Monopulse tracking technique using higher order waveguide modes is utilized. An investigation was conducted to clarify the rainfall effect and the effect of oscillator phase noise on the tracking receiver. An autotrack system is to be manufactured on the basis of these studies. Experiments were performed using the medium capacity communications satellite. No cross coupling was seen in the pull-in patterns. Sufficiently good results were obtained in tracking accuracy: less than 0.005° (peak value) under normal conditions, and less than 0.01° under an average wind velocity of more than 20 m/s.     

中继卫星天线指向控制策略研究

首先根据中继卫星系统中中继卫星跟踪用户星的要求,定义了中继卫星天线坐标系,推导出了中继卫星天线对用户星的跟踪规律,通过该跟踪规律可以推出中继卫星跟踪用户星时天线方位和俯仰轴转角,为了保证中继卫星与用户星之间的通信,中继卫星单址天线需要精确的指向用户星;然后详细描述了天线指向控制概念,并且设计了星上自主控制方案,星上自主控制方案由捕获和自动跟踪模式组成,一方面设计了天线捕获过程,另一方面对自动跟踪模式的天线步进逻辑进行了合理选择;最后根据推导的跟踪规律,以不同轨道的用户星作为跟踪目标,对所设计的天线指向控制系统进行了数学仿真,并且通过对仿真结果的分析验证了中继卫星单址天线指向性能。     

单级感应线圈炮能量转换效率研究

在单级感应线圈炮的发射过程中,随着电容器组放电电压、电容量以及电枢初始位置的变化,弹丸出口速度和系统能量转换效率也将随之发生变化.为获得其中的规律,建立了单级感应线圈炮的数学模型,仿真分析了电容器组放电电压、电容量以及电枢初始位置对弹丸出口速度及系统能量转换效率的影响.分析结果表明,随着放电电压增加弹丸出口速度几乎呈直...     

High Dynamic GPS Receiver Using Maximum Likelihood Estimationand Frequency Tracking

A new high dynamic global positioning system (GPS) receiver ispresented and its performance characterized by analysis,simulation, and demonstration. The demonstration receiver is abreadboard model capable of tracking a single simulated satellitesignal in pseudorange and range rate. Pseudorange and range rateestimates are made once every 20 ms, using a maximum likelihoodestimator, and are tracked by means of a third-order fadingmemory filter in a feedback configuration. The receiver trackspseudorange with rms errors of under 1 m when subjected tosimulated 50 g, 40 g/s circular trajectories. The tracking thresholdis approximately 28 dB·Hz, which provides 12 dB margin relativethe the minimum specified signal strength, assuming 3.5 dB systemnoise figure and 0 dB antenna gain.     

一种基于3D扫描的航天器跨舱对接波导组件位姿测量方法

提出了一种基于Handyscan 700和Geomagic Control的非接触式位姿测量方法。该方法采用手持式便携3D扫描设备Handyscan 700,具有测量速度快、测量精度高的优点。在波导组件位姿测量试验中,本方法解决了航天器跨舱波导组件位姿无法高效测量的难题,实现了跨舱波导组件舱内部分在舱板合舱前就可安装到位,降低了总装风险,提高了波导组件总装效率。     

机载卫星通信天线引导概率分析

针对某机载Ka频段卫星通信天线的使用环境,论述其天线角跟踪系统在捷联航姿设备引导下,天线主波束指向卫星目标位置的概率,分析影响天线角跟踪系统引导概率的主要因素,通过消减系统中大误差源保证了天线引导概率,通过扩展主波束指向空域提高了目标落入概率。计算数据和试验验证表明,给出的分析方法可行,设计策略有效。     

定向通信系统天线波束指向误差分析

对影响定向通信系统天线波束指向误差的因素进行了分析,给出了一种特殊情形下波束指向误差与姿态角的关系式,同时给出了一般情形下基于最小二乘估计的波束指向误差与姿态角关系的推导方法.给出的关系式和方法对分析定向通信系统波束指向误差提供了理论依据,有助于评估定向通信系统的波束对准情况.     

Beam-pointing error compensation method of phased array radar seeker with phantom-bit technology

A phased array radar seeker (PARS) must be able to effectively decouple body motion and accurately extract the line-of-sight (LOS) rate for target missile tracking.In this study,the real time two-channel beam pointing error (BPE) compensation method of PARS for LOS rate extraction is designed.The PARS discrete beam motion principium is analyzed,and the mathematical model of beam scanning control is finished.According to the principle of the antenna element shift phase,both the antenna element shift phase law and the causes of beam-pointing error under phantom-bit conditions are analyzed,and the effect of BPE caused by phantom-bit technology (PBT) on the extraction accuracy of the LOS rate is examined.A compensation method is given,which includes coordinate transforms,beam angle margin compensation,and detector dislocation angle calculation.When the method is used,the beam angle margin in the pitch and yaw directions is calculated to reduce the effect of the missile body disturbance and to improve LOS rate extraction precision by compensating for the detector dislocation angle.The simulation results validate the proposed method.     

Exact Target Angular Coordinates from Biased Radar Measurements

Exact and simplified expressions are derived for the calibration of raw target coordinate measurements obtained from a tracking radar, The measured target position in angle is indicated by the displacement of the antenna boresight. The true target position, however, deviates from this measured value because of such system biases as tilt (leveling error), nonorthogonality of axes, collimation error, dynamic lag, etc. These and other biases are accounted for in this paper. The pedestal configuration assumed is an elevation over azimuth mount. A noise-free environment is also assumed.     

An approach to radiated testing of installed airborne Doppler radarwith weather/windshear detection capability

Numerous documents were reviewed to verify radar parameters needed to analyze and present the tester concept described herein. The weather and windshear models defined use the identical criteria established for the Doppler radar in terms of F-factor. The basic concept of the tester is to transmit coherent simulated radar returns in response to the airborne radar's transmission while mounted on a tripod in the far field of the radar when parked on the ramp. The varying amplitude of the received radar pulses are analyzed and put into memory as the tester antenna is illuminated by the scanning main beam and side lobes of the radar's antenna patterns. The tester controls the power of its outputted simulated radar returns in inverse relation to the power of the received radar pulses. These simulated radar returns, outputted into the main beam and/or side lobes of the scanning radar antenna, are interpreted by the radar system as received in the main lobe. The tester transmissions, incorporating microburst, storm and gust front models, previously defined, can thereby test the aircraft radar system performance in various hazard environments. The tester is designed to: verify operational performance of the radar; demonstrate installed radar performance; verify crew reports and minimize radar or LRU's removal for maintenance; test before and after a repair; and verify radome effects on radar performance