Ka波段高增益圆极化机载微带天线阵的设计与实现

设计、分析、制作了一种工作在Ka波段的4单元高增益、圆极化机载微带天线阵列。利用顺序旋转阵列和串并馈方式的微带线网络馈电,显著改善了天线的轴比带宽和驻波带宽,减少了馈线损耗,实现了高增益。采用L型微带调配枝节对贴片单元进行匹配,便于组阵,解决了阵列空间布局不合理的难题;馈电网络和天线单元集成在同一介质基板上,易于加工和制作。测试结果表明:该天线阵具有高增益和良好的圆极化特性,从而证实了该方法的正确性和实用性。本文所设计的天线由于具有体积小、质量轻、结构紧凑、易于集成等优点,在机载相控阵雷达以及卫星通信系统中具有很好的应用前景。     

单脉冲双极化天线阵列设计

文章研究了单脉冲双极化天线阵列。天线阵混合馈电微带单元由共面微带线馈电和缝隙耦合微带线馈电两者结合形成,"十"字形微带单脉冲比较器与天线阵同面,具有结构紧凑、加工方便和成本低的优点。经仿真验证,在工作频带内其辐射单元双端口隔离度高于34dB;并且2个极化端口在其对应主平面方向的副瓣电平均低于-20dB。天线可适用于新一代多极化雷达系统。     

一种新型双线极化BD2 B3抗干扰天线设计

设计了一种双线极化BD2B3抗干扰天线单元,采用2个幅度相等相位相差90°的馈电点,产生幅度相等相位正交的2个线极化波实现双线极化,用该天线单元进行抗干扰阵列组合,能够有效减小天线阵列的体积。     

新型超宽带共面波导结构天线的设计

设计了一款共面波导馈电的新型超宽带平面天线,该天线印刷在介电常数为4．4的FR4覆铜介质基板上,尺寸为20mm×30min×1．2mm,利用仿真软件HFSS对天线参数进行优化仿真。调节辐射贴片上各枝节的长度与宽度,通过不同谐振点的耦合来展宽频带宽度,可实现天线频带宽度为3-11．7GHz（S11〈-10dB）,相对带宽达到119％。按照优化尺寸对天线进行加工,实测数据与仿真值基本吻合。结果表明,该天线不仅可以实现超宽频带,而且结构简单,尺寸小,易于集成。     

一种W—V型宽带微带天线的设计与仿真

提出一种新型的宽带微带探针馈电贴片天线。天线采用空气介质层,在W形接地板顶端利用同轴探针馈电V形贴片电线,这种设计使探针在介质基板中长度较短,产生的电感较小,同时增加了介质基板的厚度,因此使天线得到较大的工作带宽。选择合适的天线尺寸,通过仿真软件HFSS测出的阻抗带宽（VSWR≤1．5）达到48．6％,覆盖2．12GHz-3．48GHz（S波段）频率范围。     

舱外航天服天线设计及仿真验证

为提高未来新型舱外航天服天线的性能,解决将天线层与服装热防护层共形和使馈电网络适应舱外环境温度的问题,提出采用织物振子天线形式作为舱外航天服天线整体方案,从天线层结构和馈电网络两方面对舱外航天服天线进行结构设计。根据舱外航天服天线安装位置,建立了相应的仿真模型,采用天线辐射体、热防护层及服装整体一体化电磁仿真技术,对其增益覆盖性进行分析。仿真结果表明:背包方案的舱外航天服天线全向性和增益覆盖性性能较好,增益在-12dBi时收发天线的覆盖性可以达到90%以上。     

微带电路和天线的时域仿真

介绍了运用FDTD设计和分析微带电路和天线的基础理论,分析了误差产生的原因。利用FDTD法分别对微带传输线、矩形微带贴片天线和微带分支耦合器进行了仿真和特性分析。     

一种新型低剖面双频微带导航天线

设计了一种可以同时工作在BD2B3与GPS L1频段的低剖面微带导航天线,采用多调谐回路技术实现了天线双频工作。该天线方便调试与实现,可以应用于要求天线剖面较低的载体。     

一种低副瓣波纹喇叭天线的设计与实现

文章设计了一种高斯分布的波纹喇叭天线,具有增益高、转换效率高、交叉极化低、相位中心不随频率变化的特点。该天线采用正交馈电,结构简单紧凑,以双线极化或圆极化方式工作。根据天线设计参数,建立了天线模型,进行了优化设计。仿真和实测结果表明,天线在频率34～36 GHz范围内,增益大于20dBi,方向图在E面和H面具有良好对称性,副瓣电平不大于-26 d B,驻波比小于1.5,整体性能满足工程应用要求。     

基于噪声匹配的有源接收天线设计

为了提高接收天线的增益和灵敏度,采用将天线与低噪声放大器集成到一起设计的方案,将天线的输出阻抗作为放大器的源阻抗,省略了天线与放大器之间的阻抗匹配网络。通过调节天线馈电系统的尺寸调节天线阻抗,使其等于放大器的最佳源阻抗。利用HFSS仿真软件计算天线的辐射特性及阻抗,用ADS Designer软件对低噪声放大器进行优化设计。利用2SC5507晶体管设计了一个工作于2．0GHz的与低噪声放大器集成在一起的缝隙耦合微带天线,所设计的噪声系数为1．664dB,放大器增益为16．75dB。     

有翼高超声速再入飞行器气动设计难点问题

有翼高超声速再入飞行器是近年来的研究热点,气动设计是飞行器设计的关键。为了更清楚地认识有翼高超声速再入飞行器气动设计的难点问题,对有翼高超声速再入飞行器的发展、优势及总体任务剖面进行了介绍,从5个方面详细介绍了该类飞行器气动设计的难点问题,包括多约束复杂面对称气动布局设计、高温真实气体效应对气动特性影响、天地差异与天地换算方法、反作用控制系统(RCS)喷流干扰对气动特性的影响以及气动数据不确定度等,简要阐明了这些难点问题对总体设计的重要性以及初步的解决思路,为有翼高超声速再入飞行器气动设计提供了一些参考。     

Simulation and Analysis of Crashworthiness of Fuel Tank for Helicopters

Crashworthiness requirement of fuel tanks is one of the important requirements in helicopter designs. The relations among the protection frame, textile layer and rubber layer of the fuel tank are introduced. Two appropriate FE models are established, one is for an uncovered helicopter fuel tank without protection frame, and the other is for fuel tank with protection frame. The dynamic responses of the two types of fuel tanks impinging on the ground with velocities of 17.3 m/s are numerically simulated for the purpose of analyzing energy-absorbing capabilities of the textile layer and protection frame. The feasibility of the current crashworthiness design of the fuel tank is examined though comparing the dynamic response behaviors of the two fuel tanks.     

突破技术趋同，波音再现竞争优势

 波音公司面临着来自空客公司的巨大挑战,企业战略性创新才是公司成功的关键。为此波音公司的全部战略性研究集中在扩大产品的差异性上,体现在3个方面：电子化（e-Enabled）运营环境、整体复合材料机身部件的制造技术和支持波音787客机的全球协同环境（GCE）。     

The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow

This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig.Measurements of heat transfer from the discs and tangential velocities are presented.The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine.Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air.Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows(Re up to 5×106 and Rez up to 2×105).Two different builds have been tested.The most significant difference between these two build configurations is the size of the annular gap between the(non-rotating) drive shaft and the bores of the discs.The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method.The velocity measurements were made using a two component,LDA system.The heat transfer results from the discs show differences between the two builds.This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity.There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig.For the narrow annular gap,there is an increase of non-dimensional tangential velocity V/Ωr with radial location to solid body rotation V/Ωr=1.For the wider annular gap,the non-dimensional velocities show a decrease with radial location to solid body rotation.      

ν-gap度量及其在飞行控制律评估中的应用

 传统控制律评估方法主要用于单输入单输出（SISO）系统，且对模型参数摄动考虑不够全面,针对这些不足，研究了ν-gap度量方法。在介绍系统广义稳定裕度相关概念的基础上，给出了ν-gap度量的定义、特点和性质以及近似摄动模型的计算，提出ν-gap度量评估控制律的步骤。实例结果表明，该方法不仅克服了上述传统评估方法的缺陷，而且还有根据所求的各摄动影响情况忽略影响小的元素，以减少计算量及可以找到最坏情况下的参数摄动组合等优点。     

临近空间飞行器测控与信息传输系统频段选择

 临近空间飞行器是高性能信息化武器平台,测控（TT&;C）与信息传输系统是其信息保障的核心,而选择合理、可行的频段是展开系统设计的前提和基础。频段选择影响到整个技术方案的制定,是一个需综合考虑、影响深远并具有战略意义的关键问题,从国际电联（ITU）国际标准、高速数传、接收信噪比（SNR）、“三抗”、超视距中继、黑障、雨衰以及设备研制成熟度8个方面全面、细致论证了近空间平台测控系统的频段选择问题,最终得出在视距链路中以Ka频段为宜,在超视距链路中以Ku/Ka双频段为宜的结论。     

基于弯曲激波压缩系统的高超声速进气道反设计研究进展

总结了近十年来弯曲激波压缩研究的主要成果。提出了弯曲激波压缩系统的新概念,即利用特殊设计的楔形弯曲压缩面或空间弯曲压缩面,产生一系列与前缘弱激波相互交汇或叠加的压缩波系,从而使前缘激波弯曲,形成特殊的弯曲激波,它与波后的等熵压缩波来共同完成对气流的压缩。在此基础上,实现了由给定出口气动参数的超声速内流道反设计,实现了由给定压缩面压力分布和给定压缩面马赫数分布要求的型面反设计,实现了由给定激波波面的压缩型面反设计。研究证明,弯曲压缩面-弯曲激波压缩系统具有良好的综合气动性能,为高性能高超声速进气系统的气动设计提供了一种全新的设计方法。     

Integrated Entry Guidance for Reusable Launch Vehicle

A method for the implementation of integrated three-degree-of-freedom constrained entry guidance for reusable launch vehicle is presented. Given any feasible entry conditions, terminal area energy management interface conditions, and the reference trajectory generated onboard then, the method can generate a longitudinal guidance profile rapidly, featuring linear quadratic regular method and a proportional-integral-derivative tracking law with time-varying gains, which satisfies all the entry corridor constraints and meets the requirements with high precision. Afterwards, by utilizing special features of crossrange parameter, establishing bank-reversal corridor, and determining bank-reversals according to dynamically adjusted method, the algorithm enables the lateral entry guidance system to fly a wide range of missions and provides reliable and good performance in the presence of significant aerodynamic modeling uncertainty. Fast trajectory guidance profiles and simulations with a reusable launch vehicle model for various missions and aerodynamic uncertain-ties are presented to demonstrate the capacity and reliability of this method.     

Experimental Study on Effects of Fuel Injection on Scramjet Combustor Performance

In order to investigate the effects of fuel injection distribution on the scramjet combustor performance, there are conducted three sets of test on a hydrocarbon fueled direct-connect scramjet test facility. The results of Test A, whose fuel injection is carried out with injectors located on the top-wall and the bottom-wall, show that the fuel injection with an appropriate close-front and centralized distribution would be of much help to optimize combustor performances. The results of Test B, whose fuel injection is performed at the optimal injection locations found in Test A, with a given equivalence ratio and different injection proportions for each injector, show that this injection mode is of little benefit to improve combustor performances. The results of Test C with a circumferential fuel injection distribution displaies the possibility of ameliorating combustor performance. By analyzing the effects of injection location parameters on combustor performances on the base of the data of Test C, it is clear that the injector location has strong coupled influences on combus- tor performances. In addition, an inner-force synthesis specific impulse is used to reduce the errors caused by the disturbance of fuel supply and working state of air heater while assessing combustor performances.     

(高)超声速流动试验技术及研究进展

近年来,与高速飞行器相关的(高)超声速流动受到了极大的关注。这类流动所具有的非定常性、强梯度和可压缩性对试验方法和风洞设计技术提出了挑战。超声速纳米示踪平面激光散射(NPLS)技术是由作者所在团队研发的非接触光学测试技术。它能够以较高的空间分辨率来揭示超声速三维流场的一个瞬态剖面的时间解析的流动结构。介绍了NPLS技术以及基于NPLS开发的密度场测量、雷诺应力测量和气动光学波前测量等方法,并回顾了这些技术在超声速边界层、超声速混合层、超声速压缩拐角、激波/边界层相互作用和光学头罩绕流等流动中的应用,清晰地再现了边界层、混合层、激波等典型流场结构及其时空演化特性。另外,为了模拟和研究高空大气条件下边界层自然转捩和超声速混合层的转捩特性,介绍了高超声速静风洞、超-超混合层风洞的设计技术以及层流化喷管的设计方法。