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研究了有源相控阵天线的低成本设计思路和数字技术新方法。首先详细地分析了有源相控阵天线的系统构架和成本组成;然后从系统总体的角度,探讨了低成本数字阵列相控阵天线设计方法;最后提出了采用宽带宽角扫描的可重构设计技术来降低有源相控阵天线的成本。提出的有源相控阵天线低成本设计新方法具有很好的工程实用价值和科学意义。 相似文献
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本文以调试数字卫星接收系统的实际经验为基础,简要介绍了数字卫星接收系统的组成、卫星接收天线的粗调和细调,以及调试天线和接收机过程中需要注意的问题。 相似文献
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大型数字阵列雷达的天线系统由辐射单元和成千上万个数字收发组件(DTR)组成,极其庞大与复杂,雷达的工程化和安全性是系统的难点问题,微波光子学将对未来大型数字阵列雷达产生重大影响,基于微波光电实现阵列信号远程收发与传输技术,对未来大型数字阵列雷达提出一种构想,使雷达天线系统由辐射单元和模拟光电收发模块(OTR)组成,天线系统实现轻质、低成本、远程安装,有效改善大型数字阵列雷达的架设灵活性和使用安全性,同时光电数字阵列模块(ODAM)设计空间将更加宽容,有利于雷达综合性能的提升。 相似文献
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第2代数字蜂窝系统已经成熟,在多址方式上主要采用TDMA和CDMA。但是第2代系统采用的窄带CDMA由于受到传输频带窄的限制,未能真正发挥CDMA的特性。因而移动通信系统在经历了第1代模拟系统和第2代2G数字系统之后,正向以宽带CDMA技术为核心的第3代3G数字移动通信系统发展。CDMA技术本身为顺利引进包括智能天线在内的现代数字信号处理技术创造了条件。可以说,智能天线是3G区别于2G系统的关键标志之一。现在,智能天线已成为国内争取自主知识产权的一个热点领域。一、 智能天线的基本概念人们研究智能天线的最初动机是,… 相似文献
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本文描述了联合战术微波着陆系统(TTMLS)机载角度接收机中的信号处理技术,即如何利用综合化数字电子设备设计技术和与飞机结构有关的天线,实现全天候进场和着陆引导.综合化电子设备能在飞机所处的一个极宽范围内检测MLS信号并进行信号处理,为整个军用飞行控制系统和飞机座舱显示给出水平、垂直和航距引导信息.该系统能保证陆海空三军及民用导航的兼容性. 相似文献
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许多人可能会认为卫星电视的理论很复杂,需要涉及大量的数字知识。其实不然,只需少量的数字知识就可以理解这些原理。我们在这里对接收卫星电视的基本原理作个基本的介绍,以简单的方式描述可能遇到的各种各样卫星天线和前端组合的基本操作和功能。本文以讨论天线为主,着重介绍几种比较普遍的天线。 一、天线的基本知识 天线的作用是收集和接收远处的卫星发出的微弱的微波信号,把它引导到一点然后才开始处理。由此可知。天线具有内在的信号功率增益,可以使用各种安排来达到这个目的。最广为人知的天线是抛物面反射器(即碟 相似文献
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阐述了航天统一测控站在卫星和飞船发射过程中,实时数字引导中的数据处理。其中包括数据变换、数据的时间比对、外推估值等方法,提高了数字引导精度和设备的角度捕获能力。 相似文献
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讨论了当极低频水平低架天线场地周围的地层导电率呈现各向异性时对水平低架天线方向性和发射效率的影响.分析了导电率各向异性条件下的地层表面阻抗,导出了极低频电波在地-电离层波导中传播的模方程,给出了典型条件下各向异性的导电率参数对TM0波模在各个方向上的相速和衰减率影响的规律及导电率各向异性和各向同性情况下天线方向图的比较,得出了各向异性的导电率对天线方向图和发射效率有较大影响.对设计极低频天线及其工程建设具有理论指导意义. 相似文献
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The authors investigate analytically and experimentally the properties of the mig (microstrip inset guide), highlighting its features with respect to microstrip and its applications to antenna circuitry. The method used in the analysis is the transverse resonance diffraction (TRD) method in the space domain. The authors discuss dispersion of the first three modes, field distribution, characteristic impedance, and losses of the fundamental mode. They report the experimental antenna characteristics of an array of longitudinal strips, designed as a cascade of mig sections alternating with idg (inset dielectric guide) sections, showing good gain input match and pure polarization 相似文献
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It has been demonstrated recently that it is possible to guide broadband Terahertz pulses utilising a novel coaxial waveguide. This technique is hindered by the difficulty in exciting the radially polarised fundamental mode of the waveguide. To optimise mode matching, a novel radially symmetric photoconductive Terahertz antenna is proposed. Using finite element method simulations and analytical calculations, it is shown that this antenna can generate the desired radial polarisation. 相似文献
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Yongmei Pan Shanjia Xu Ke Wu 《Journal of Infrared, Millimeter and Terahertz Waves》2006,27(7):961-974
A new millimeter wave leaky wave antenna is presented in this paper, which is a modification of the groove guide with an asymmetric conductor strip by introducing a dielectric slab into the conductor plane region of the groove guide antenna. The leakage property of the new antenna is carefully examined through calculations of an equivalent network, which is developed here with taking into account the coupling between different modes to guarantee the calculating accuracy. It has been found that the new leaky wave antenna is of larger leakage constant than that for the original groove guide antenna because of the introduction of the dielectric slab. Extensive numerical results of the leakage characteristics are given to establish useful guidelines for the design of the new type groove guide leaky wave antenna. 相似文献
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采用卫星仿真工具包对全球卫星导航系统包括GPS、Galileo、Compass等导航卫星星座的地面站天线方位、俯仰跟踪特性进行了仿真分析,以大口径地面接收天线为例讨论了可行的地面站天线座架形式和跟踪体制.并综合常规卫星通信抛物面天线精度分析方法和测控雷达天线的精度分析方法对跟踪精度进行了系统的分析,分析结果可作为今后类... 相似文献
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From a cost effectiveness point of view, the shipborne antenna is usually considered the most critical component in a shipborne terminal for maritime satellite communications (MARSAT). For possible use in such a system, a high gain autotrack antenna has been developed. The antenna utilizes a combined electronical and mechanical beam steering realized with two planar phased arrays mounted on a mechanical axis. The antenna system is designed for unmanned operation, utilizing an automatic search-and-track mode. After acquisition of a beacon signal from the satellite, a monopulse track mode keeps the antenna pointing position locked, to the direction of incident beacon signal, irrespective of the motions of the ship. Attention has been paid to multipath effects that may occur, in particular reflections from the surface of the sea. This paper is concerned with the design background and the development of the antenna system. 相似文献
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Strip dielectric wave guide antenna-for the measurement of dielectric constant of low-loss materials
Alok Kumar Rastogi A. K. Tiwari R. P. Shrivastava 《Journal of Infrared, Millimeter and Terahertz Waves》1993,14(7):1471-1483
The value of dielectric constant are the most important parameters in material science technology. In micro-wave and millimeter wave circuits using dielectric materials the values of this parameters should be known accurately. It is observed that the number of methods are reported in litrature, however these methods impose difficulties in experimentation and are not very accurate. In this paper a novel approach to the measurement of the dielectric constant of low loss materials at micro-wave and millimeter wave frequencies has been discussed. In this method by using antenna theory, a metallic strip dielectric guide is taken in to constideration and band reject phenomenon of dielectric antenna is used. Frequency response of an antenna in band reject mode is a function of the dimensional parameters, such as the metallic strip period, the profile of the metallic strip and the dielectric constant of the material used. Hence if one measure the frequency responce of the antenna in band reject mode, the dielectric constant of the material is determined provided all other parameters are known. This method gives a direct measure of dielectric constant and is quite accurate as computer techniques are used for evaluating the dielectric constant. This method verified experimentally also. 相似文献