共查询到18条相似文献,搜索用时 140 毫秒
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时域近场测量作为一种新发展起来的天线测量技术,具有和通常的频域测量不同的独特优势,它能得到天线的时域特性和宽带特性.首先介绍了时域平面近场测量系统的构成,为了能对雷达进行测量,系统采用了使用矢量信号源模拟产生复杂雷达信号的方案,并对标准增益喇叭进行了验证测试,把测试结果和理论仿真、频域近场测试结果进行了比对,证实了时域... 相似文献
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天线在高功率微波辐照下的响应特性分析是研究后端接收电路干扰特性及毁伤效应的依据。以典型的平面阿基米德螺旋天线为研究对象,利用理论分析和时域有限积分方法相结合,研究了该天线在高功率微波场作用下的时域和频域响应特性,并开展了相关的试验验证。结果表明,通过Friis 传输理论预估的发射功率和实际发射功率的误差在1 dB 量级,仿真得到的响应信号和测试得到的响应信号在时域波形和频谱特性上均吻合较好,仿真方法正确有效,为高功率微波照射下天线响应特性的研究提供了技术支撑。 相似文献
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短波通信受多径衰落、干扰复杂等影响严重。空时分组码(Space Time Block Code,STBC)技术在无需增加频谱资源和天线发射功率的前提下,可以利用多输入多输出(Multiple-Input Multiple-Output,MIMO)信道提供的分集增益提升传输可靠性。分析短波MIMO研究现状,提出短波单载波STBC频域均衡(Frequency-Domain Equalization,FDE)系统架构,针对短波信道引入的码间干扰研究MIMO MMSE-FDE均衡技术,并将单载波STBC频域均衡与时域均衡及短波现有波形进行仿真对比。仿真结果表明,相较于短波现有波形,单载波STBC频域均衡系统的可靠性有较大幅度提升,且性能与STBC时域均衡接近,但计算复杂度远低于STBC时域均衡。 相似文献
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阻性加载技术可以有效拓展天线带宽、降低时域振铃.该文以双纽线构成平面印制天线的辐射臂, 分析阻性加载对其频域和时域特性的影响.通过数值仿真, 讨论了天线在两种阻性加载方式下阻抗带宽和时域波形的变化.设计了一款指数型微带转平行双线的巴伦, 并对巴伦和天线进行了加工及测试.测量结果表明, 天线时域波形拖尾振铃小于10%;在0.8~6 GHz频带内, 天线单元回波损耗小于-10 dB.将天线与雷达收发系统集成后, 进行地下目标探测实验.雷达探测结果成像清晰、浅层目标分辨率较高.该天线具有超宽带、低振铃、紧支撑等特点, 可满足便携式探地雷达的工程化应用需求. 相似文献
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暗室为卫星导航接收机抗干扰测试提供了全面有效的测试环境,极大地提高了抗干扰性能定量测试与评估能力。但暗室的静区性能、结构尺寸、天线布局等因素会对抗干扰性能测试结果产生影响。基于多径信号天线接收模型、阵列波程差等效模型和信号来向天线映射模型,通过仿真量化分析了干扰多径信号、有限距离下近场效应和来波方向误差对抗干扰测试结果的影响。结果表明,暗室静区性能的提升可降低干扰多径信号对零陷位置的拉偏;不同暗室尺寸对应不同的零陷深度测试,需根据测试需求折中选择;布设暗室天线应依据预设的被测阵列天线和测试场景。结果可为暗室设计、抗干扰测试方案选定和测试结果分析提供参考,提升抗干扰测试的可信度。 相似文献
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Dau-Chyrh Chang Chao-Hsiang Liao Chih-Chun Wu 《Antennas and Propagation Magazine, IEEE》2004,46(4):27-37
There are several types of CATRs (compact antenna test ranges) used in antenna-pattern measurements. An offset reflector is generally used to generate the quiet zone of a CATR. Serrated edges, rolled edges, or R-cards are generally chosen along the reflector's edge to reduce the edge-diffraction field inside the quiet zone of the CATR. In order to reduce stray signals from the environment, a high-quality RF anechoic chamber is required for a CATR. In this paper, a new type of CATR, without either a reflector edge treatment or an RF anechoic chamber, is developed. A commercially available DBS (direct-broadcast satellite) reflector antenna, without edge treatment, is used as the reflector antenna of the CATR to generate the quiet zone of the antenna test range. In order to improve the quiet zone's performance, the fields due to feed spillover, edge diffractions, and other stray signals are gated out by the ITDAMS (impulse time-domain antenna measurement system). The RF interference in the environment can also be reduced by time synchronization and pulse integration of the impulse time-domain antenna measurement system. In order to verify the capabilities of the proposed CATR, three kinds of antennas (a low-directivity horn antenna, a high-directivity 60 cm direct-broadcast satellite reflector antenna, and a 25 cm Ka-band Cassegrain LMDS - local microwave distribution system - antenna) were measured by the proposed CATR. The antenna-pattern results agreed quite well with those of a near-field range and a far-field range. 相似文献
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Welch T.B. Musselman R.L. Emessiene B.A. Gift P.D. Choudhury D.K. Cassadine D.N. Yano S.M. 《Selected Areas in Communications, IEEE Journal on》2002,20(9):1778-1782
Ultra-wideband (UWB) communication systems are investigated for their ability to operate in dense multipath environments. While a great deal of time and effort has been spent characterizing both the indoor and outdoor UWB channels, the effects of human body interaction with a close proximity UWB antenna remains unexplored. Measurements of a commercially available UWB antenna performance in an anechoic chamber and in various indoor multipath environments were conducted. Comparisons of these measurement results indicate that while the human body creates a deep (23.6 dB) in a light multipath environment, this is drastically reduced (6.8 dB) in a dense multipath environment. 相似文献
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The paper describes a technique for analyzing antenna measurements and removing reflected components present in measurements performed in echoic environments. The method is based on digital signal processing methods, and frequency-domain measurements are used to design a discrete-time, finite impulse response digital filter using least-squares methods. The frequency response of the filter is equal to the transmission coefficient measurements performed in an anechoic chamber. In order to verify the method, processed measurements of mutual coupling between stacked patch antennas were compared to the computer simulations of anechoic response, and a very close agreement was achieved. 相似文献