高频表面波雷达发射天线及其对输入信号要求的研究

高频表面波雷达因具有反隐身、抗反辐射导弹和超视距探测等特性而受到广泛重视。本文从提高雷达发射天线的增益出发,采用矩量法对对数周期偶极天线及扇形阵进行了理论分析,给出了它们的仿真图形,并在此基础上讨论了阵元输入激励的偏差对阵列方向图的影响,这对高频表面波雷达发射天线的设计具有一定的指导意义。     

高频地波雷达天线阵抗电离层干扰

高频表面波雷达是近年发展起来用于超视距监测大面积海洋环境的工具,但由于天线本身的特性和天线场的限制,发射天线辐射波束E面有一定的宽度或向上翘起一定角度,其辐射的电磁波能量除了沿海面绕射传播外,还有一部分能量以一定的角度向上半空间辐射,与电离层和所经路径上的散射体相互作用后,其后向散射信号又以原路径回到雷达,并对雷达形成严重的自干扰.本文基于自适应天线理论,在对功率倒置算法改进的基础上,介绍了一种自适应对消电离层自干扰新方法,雷达现场观测实验表明,本方法可以抑制电离层自干扰.     

岸基远程高频表面波雷达小型宽带天线系统的设计

从高频表面波雷达天线工程的角度出发,基于对数周期天线的设计理论,优化设计了一副小型 宽带发射天线;基于端射阵理论,优化设计了一副小型宽带、具有大前后比的双鞭天线,并以此作为阵列天线的基本单元组成六元均匀线阵。文中分析了收发天线的工作原理,并给出了计算机模拟结果。     

智能天线在移动通信系统中的应用

1智能天线定义和技术特点 智能天线原名自适应天线阵列(AAA,Adaptive Antenna Array).最初的智能天线技术主要用于雷达、声纳、抗干扰通信、定位、军事方面等,用来完成空间滤波和定位.     

现代低空警戒雷达抗干扰技术应用

雷达抗干扰性能是评价雷达整机性能的重要指标之一。本文阐述了一种现代低空警戒雷达的抗干扰技术,通过试验分析该雷达中超低副瓣天线技术、自适应频率捷变技术、数字脉冲压缩技术、MTI和AMTI技术等。     

智能天线在移动通信系统中的应用

1智能天线定义和技术特点 　　智能天线原名自适应天线阵列(AAA,Adaptive Antenna Array).最初的智能天线技术主要用于雷达、声纳、抗干扰通信、定位、军事方面等,用来完成空间滤波和定位.……     

电波传播与天线 天线与天线阵

0626101LEO微卫星自适应零位天线阵列抗干扰无线分组网络特性分析=Performance Analsysis of Anti-Interfer-ence Wireless Packet Networks for LEO Micro-Satellitewith Adaptive Nulling Antenna Array〔刊,英〕/刘海涛//中国邮电高校学报(英文版).—2006,13(2).—10-14(E)0626102表面波激励等离子体天线的原理与实现〔刊,中〕/袁忠才//电子信息对抗技术.—2006,21(4).—38-41(G)等离子体天线,因其具有许多独特的性质而受到各国军方的广泛关注。从表面波激发产生等离子体的基本原理出发,分析了表面波在等离子体中的传播特性,并…     

高频地波海态探测雷达天线技术

详细介绍和总结了40多年来国内外高频地波雷达天线的发展状况,系统分析了高频地波雷达天线设计应考虑的若干实际和关键性问题,指出了高频地波雷达天线的发展趋势,基于某高频地波雷达系统设计要求,提出并设计了一种新的高频地波雷达天线方案.     

海岸监视高频表面波雷达系统中应用水平振子天线自适应抑制天波干扰

介绍了在高频表面波雷达（ＨＦＳＷＲ）中，采用水平振子天线抑制天波干扰的自适应系统的初步研究结果。四个水平振子，两两正交排列，附加到通常采用垂直极化天线（ＶＰＡ）的ＨＦＳＷＲ系统中。从振子接收的数据与从ＶＰＡ接收的数据相关，以便ＶＰＡ自适应地估算和对消掉干扰。研究结果表明，该项技术对抗所研究的干扰效果很好。干扰加噪声功率我达１３ｄＢ，而Ｂｒａｇｇ对干扰加噪声之比升高多达２１ｄＢ。本文对使用１个、２个     

基于LMS算法的功率放大器控制系统

高频表面波雷达对发射功率要求很高,通常会采取功率空间合成的办法使数个较小功率的发射机合成一个较大的合成发射功率。首先介绍了子天线输入信号的幅相不一致对阵方向图产生的影响,然后讨论了不同的自适应算法的优缺点,选定了一种合适的算法并给出了硬件框图。选定的自适应控制算法具有较好的收敛性和稳态失调性,计算量小,实现简单,通过单片机及其外围模数、数模转换电路能够很方便的实现功放的幅相校准系统,使功放的输出信号的相位、幅度满足要求。     

双频圆极化天线设计方法综述

根据圆极化和双频天线的设计原理,总结了双频圆极化天线的设计方法,通过不同馈电方式和谐振方式分为四类进行阐述。归纳了近几年拓展双频圆极化天线带宽的方法,从结构上分别按照微带缝隙天线、平面单极子天线和阵列天线进行介绍。列表分析了各种设计方法的实现难度和典型天线各项性能参数,最后简述了适用于双频圆极化天线小型化的优化方案,并对未来发展趋势进行了展望。     

机载共形的双环微带缝隙全向天线

机载全向天线不但要满足水平面全向的指标要求,而且要与机体表面共形设计,常规的单极子天线和微带天线均无法满足要求。提出一种双环微带缝隙天线,可以实现机载共形的全向天线。分析了系统对机载天线的要求、双环微带缝隙天线的展宽带宽的方法,并给出了该天线的设计参数和实测结果,实测结果与仿真结果一致,验证了设计方法的正确性。     

用于天线RCS减缩的分形微带贴片天线

本文给出一种分形微带天线在天线雷达散射截面(RCS)减缩中应用的示例.分形结构具有独特的空间填充性能,利用该性能可以探索分形天线在天线RCS减缩中的应用.设计出的分形天线与常规天线的辐射性能进行了比较,可以看出分形天线基本保持了原辐射性能.同时比较了两者的散射性能,可以看出分形天线有一定的RCS减缩效果.本文的内容对天线隐身有一定的借鉴作用.     

Antenna Effective Aperture Measurement With Backscattering Modulation

A scattering measurement method for antenna characterization is described. The antenna backscattering is modulated by an oscillator circuit. The modulation begins, when a known RF power is transferred to the oscillator circuit from the antenna. This enables the measurement of the effective aperture of the antenna, from which the antenna bandwidth and radiation pattern are obtained. A theory for antenna aperture measurement is developed using a simple circuit model for the antenna-oscillator system. A dipole and a PIFA with a reactive input impedance at the application frequency were measured. The antenna aperture was measured to an accuracy of 9%, and the measurements complied with simulated and measured references. The method provides simple and accurate bandwidth and radiation pattern measurements with the reactive load the antenna is designed to work with.     

Near fields of a linear antenna

The near fields of a strip antenna in free space have been computed by modifying a variational-impedance formulation. Current distributions, which vary linearly with distance near the ends of the antenna, excite strong tangential electric fields on the antenna surface. Such surface fields are avoided by choosing the axial antenna current to vary in proportion to the square root of the distance from the antenna ends. This modification of the antenna current is not necessary, however, for field calculations at distances comparable to the antenna width. The fields parallel to the antenna surface decrease with increasing distance from the antenna near the driving point and the antenna ends, but are found to increase in an intermediate range.     

机载隐蔽式短波天线研究

给出了一种用于Y7—200A运输机的隐蔽式短波天线，该天线为位于飞机垂尾前缘的回线天线，与飞机的外形共形，不影响飞机的飞行性能。在利用传输线理论与缝隙天线理论对该天线进行分析的基础上，对输入阻抗、天线与天线调谐器结合后的天线效率进行了研究，给出了该天线与KHF950电台相配合的测试试验结果，该天线能够在2．5MHz到30MHZ范围内与KHF950电台良好调谐，表明这种天线完全可以用于Y7—200A型飞机，代替原有的钢索天线。这是在国产飞机上首次使用这种天线。     

基于光子晶体的多频微带缝隙天线的设计与仿真

在普通微带缝隙天线介质基板内引入光子晶体结构,设计了一种基于PBG结构的多频微带缝隙天线,采用平面波展开法对该天线进行了理论分析,并用HFSS 10.0对该天线进行了仿真.与传统的微带缝隙天线相比,PBG结构的引入改善了微带缝隙天线的辐射特性及多频工作性能.该天线可以用于跳频通信系统中.     

One- and two-dimensional antenna arrays for microwave wireless power transfer (MWPT) systems and dual-antenna transceivers

In this work, we demonstrate novel one-dimensional (1D) and two-dimensional (2D) antenna arrays for both microwave wireless power transfer (MWPT) systems and dual-antenna transceivers. The antenna array can be used as the MWPT receiving antenna of an integrated MWPT and Bluetooth (BLE) communication module (MWPT-BLE module) for smart CNC (computer numerical control) spindle incorporated with the cloud computing system SkyMars. The 2D antenna array has n rows of 1 × m 1D array, and each array is composed of multiple (m) differential feeding antenna elements. Each differential feeding antenna element is a differential feeding structure with a microstrip antenna stripe. The stripe length is shorter than one wavelength to minimise the antenna area and to prevent being excited to a high-order mode. That is, the differential feeding antenna element can suppress the even mode. The mutual coupling between the antenna elements can be suppressed, and the isolation between the receiver and the transmitter can be enhanced. An inclination angle of the main beam aligns with the broadside, and the main beam is further concentrated and shrunk at the elevation direction. Moreover, if more differential feeding antenna elements are used, antenna gain and isolation can be further enhanced. The excellent performance of the proposed antenna arrays indicates that they are suitable for both MWPT systems and dual-antenna transceivers.     

Novel small-size directional antenna for UWB WBAN/WPAN applications

This paper presents a novel small-size directional antenna design for ultrawide-band wireless body area networks/wireless personal area networks applications. The design is based on a typical slot antenna structure with an added reflector in order to achieve directionality. The effects of different antenna parameters and human body proximity on the radiation characteristics are analyzed. Antenna measurements with an optic RF setup were performed in order to characterize the small-size antenna far field radiation pattern. The different structural antenna parameters were optimized via extensive numerical simulations. Results show that for frequencies above 3.5 GHz, where the power front-to-back ratio of the directional antenna is greater than 10 dB, its impedance is nearly the same as in the free space. It is not the case neither for the omnidirectional slot antenna nor the monopole antenna next to the body. Between 3 and 6 GHz performance of the novel directional antenna, in terms of radiation efficiency and SAR values, is significantly improved compared to omnidirectional antenna designs.     

无线通信系统中的MEMS天线

本文分析了常见的MEMS天线及其应用,包括多对称锥形弯曲缝隙微带天线、用于WLAN中的微尺度宽频天线、开关式微机械毫米波天线、微机械自适应贴片天线等,对这些天线的结构原理、制造方法及其性能做了分析。这些天线设计简单、可用CMOS工艺制造、利于集成,兼有宽频、高辐射效率、小尺度等优点。但相对普通天线而言,这些制造工艺明显复杂、尺度更微小,增加了实现难度,要实现MEMS天线批量应用,还需要在基础理论及其微细工艺进行研究。最后,对MEMS天线在无线通信系统中的应用作出展望。