基于电子定标法的天线罩电参数测试系统设计

为了提高天线罩电参数的测试精度、速度和自动化程度,设计了天线罩电参数自动测试系统.根据天线罩瞄准误差和传输效率的测试原理,阐述了基于电子定标法的天线罩电参数测试方法和系统组成.采用GPIB总线实现对系统各部分仪器的控制和通信,分析了软件设计中的关键问题以及相应的解决方法,并给出了软件流程和测试结果.测试结果和实践表明,该系统数据处理功能完善,具有较高的测量精度和测试速度.     

机载雷达罩动态电轴跟踪系统的设计和实现

机载雷达罩瞄准误差的传统测试方法有搜零法和电子定标法两种,这两种方法均采用天线支杆固定被测天线,扫描角测试范围只能达到±30°,不满足新型机载雷达±60°的要求.为了扩大扫描角测试范围,提出了动态电轴跟踪法,这种方法去掉了天线支杆,增加了一个天线定位器,利用天线定位器的运动实现天线扫描,通过雷达罩定位器和天线定位器反向运动实现被测天线和辅助天线电轴对准.完成了某机载雷达罩动态电轴跟踪系统的设计和集成工作,扫描角测试范围达到了±60°,测试精度为±(0.25×10-3) rad,满足测试要求.     

大型天线罩传输损耗测试的一种新方法

针对大型天线罩整罩传输损耗的测试问题,提出了一种新的测试方法,给出了大型天线罩整罩传输损耗计算公式和测试程序。与传统测量天线罩传输损耗的比较法相比,新的测试方法简捷、实用,不需远场标校高塔、测试天线和信号源等,仅利用卫星地面接收系统已有的设备即可测量天线罩传输损耗。该方法已用于实际工程项目的测试验收工作中,测量结果同理...     

电磁波入射角对小型机载天线罩透波率的影响测试

机载天线罩良好的透波率是保证天线系统高效工作重要因素,透波率的除了受天线罩本身状况影响外,还与电磁波的方向、频率、极化等因素有关。为解决天线罩透波率测试系统构建复杂、实现困难、测试误差大等问题,构建了一种天线罩透波率测试系统,并对不同电磁波频率、入射角下天线罩透波率进行测试,通过对平面螺旋天线罩的实测表明：低频段不同的入射角对天线罩透波率造成的影响较小,高频段大入射角时对透波率影响较大。     

动态电轴跟踪系统中扭极化问题的解决方案

动态电轴跟踪系统是常用的雷达罩电性能测试系统,该系统在使用过程中存在着被测天线扭极化的问题。对造成扭极化的原因进行了分析,确认该问题是由雷达罩转台和天线转台方位轴不同轴造成的。利用几何光学三维射线跟踪法对扭极化的危害进行了分析。提出了扭极化问题的解决方案,即将天线转台安装到随动于雷达罩方位轴的天线支杆上。同时归纳出了动态电轴跟踪系统中被测天线的安装要求。     

基于多天线GPS的船载卫星天线跟踪系统

为了克服传统的船载卫星天线跟踪系统因采用多种传感器带来的硬件成本高、软件接口复杂、系统运行速度慢和精度低等问题,提出了用多天线GPS姿态测量的方法,将GPS天线直接安装在卫星接收天线上,根据GPS各个天线的三维位置信息数据计算船载卫星天线的姿态,再由卫星的位置计算天线相对于卫星的角度并进行跟踪,实现了用一种传感器完成船载天线跟踪系统的姿态测量与控制。系统在内湖和海上进行多次测试,测试结果表明:在船体航行过程中电视信号的强度保持在60%~70%之间,对亚洲2号卫星进行移动跟踪的方位角误差的测试数据在±1.5°之间。该设计具有测试方法简单、误差小、成本低和使用方便等特点,有广泛的市场前景。     

雷达角度电视跟踪系统

雷达角度电视跟踪系统采用ＣＣＤ摄象机作为目标传感器,用软硬件结合方法测定目标坐标,再与雷达电轴位置相比较,输出目标角度误差信号,输入雷达天线驱动系统,使天线向减小目标角度误差方向运动,实现雷达天线对目标的角度自动跟踪。目标在电视视野中的位置测量是关键技术,本文着重阐述电视跟踪系统中目标坐标的录取方法。     

一种低成本MVSAT天线指向控制系统设计

针对目前卫星移动通信终端的需要,设计并实现了一种甚小孔径移动终端卫星天线指向控制系统.说明了系统的组成、工作原理和软件流程图.对指向跟踪误差进行了分析,并采用软件和硬件两个方面进行了误差消除设计,提高了天线的跟踪速度和指向精度.车载移动通信试验的测试结果表明,该系统跟踪逻辑正确,可以有效降低通信信号的发射功率,具有较高的性价比,可广泛应用于车载、船载的小型移动卫星通信终端.     

基于紧缩场暗室的相控阵天线快速测试系统设计研究

随着有源相控阵天线技术的发展,针对有源相控阵天线的快速校准及测量成为了制约其大批量产业化生产的瓶颈。本文针对有源相控阵天线校准测试效率问题设计了一套基于紧缩场暗室的相控阵天线快速测试系统I,可实现多频点、多波束的自动化测试。系统用于产品辐射特性测试,对远场波瓣图进行采集,并具备幅相校准,波束指向精度补偿,ERP和G/T等指标的测试和处理能力。     

浅析天线罩等效样件的电性能测试

本文通过对天线罩等效样件的设计要求、测试方法、测试数据的分析、等效样件的影响因素等相关内容的论述,总结以往的测试经验,通过论述为等效样件的测试分析及天线罩设计研制是否满足设计及使用要求提供参考。天线罩是保持天线及其系统正常工作的电磁窗,在天线罩研制时可通过对等效样件的性能分析来确定设计指标是否满足使用要求。     

宽带分形阵列天线的设计及其耦合分析

设计了一种新型的分形微带天线,提出了一种扩展天线带宽的方法,此方法可将天线带宽提高将近6倍,相对阻抗带宽从4.9%提高到30%左右.然后根据天线频率可重构形成的基本原理,在此宽带天线基础上引入了三个MEMS开关,通过改变开关的状态,切换调整分形微带天线组合结构,使天线能工作在三个频段,扩展了天线工作带宽.以此超宽带分形...     

Wideband sequential feeding network for Ku‐band dual circularly polarized 4 × 4 antenna array

In this article the analysis and design of a dual circularly polarized 4 × 4 antenna array operating in Ku band are discussed with emphasis on its sequential feeding network. The proposed antenna element is composed of stacked circular patches fed by a branch line coupler to introduce dual circular polarization. These antenna elements are arranged into 2 × 2 sequential fed antenna arrays with two separate sequential feeding networks for LH and RH circular polarizations. These 2 × 2 sequential fed antenna arrays are arranged to compose the proposed 4 × 4 antenna array. The proposed feeding network is implements on a single layer. Due to the coupling between the lines of the complete feeding network, matching and axial ratio of the complete antenna are degraded. Matching stubs at appropriate points on the complete feeding network are used to adjust the total performance of the designed 4 × 4 antenna array. Simulation results by using both HFSS and CST are presented for comparison. In addition, experimental verifications are presented.     

Reconfigurable antenna with loading water fluidic switch

This article presents a frequency reconfigurable antenna with loading fluidic switches. The liquid reconfigurable antenna consists of an H‐typed slot antenna and four groups of fluidic switches. The designed H‐typed slot is placed on the backside of the antenna and excited by a straight 50 Ω microstrip line on the front side. As most of the electromagnetic energy is radiated through the slot, the surface currents on the proposed antenna are concentrated on the four branches of the H‐typed slot. Four fluidic switches fabricated by using 3D printing technology are located at the ends of the four branches of the H‐typed slot, aiming to adjust resonant frequency of the antenna. Due to the symmetry of antenna structure, five states can be obtained by loading and unloading liquid distilled water in the fluidic switches, which provides five switching frequencies cover from 3.38 to 3.83 GHz. Advantages such as fast switching speed, low cost, easy fabrication, and high radiation efficiency are achieved by the proposed reconfigurable antenna, making it a good candidate for multifunctional antenna application.     

On the multi‐resonant antennas: Theory,history, and new development

A survey of multi‐resonant antennas is comprehensively presented, with emphasis on theoretical framework, design approaches, and practical examples. This article begins with a brief history of the multi‐resonant dipole theory, and then concentrates on the design approaches that have been developed to typical, basic antenna elements, for example, electric dipole antenna, slotline antenna, loop antenna, complementary dipole antenna, and microstrip patch antenna. Design examples for different practical applications are then raised. In final, the multi‐resonant antenna design approach is summarized and compared to some relevant antenna design techniques.     

Design and fabrication of miniature antenna based on silicon substrate for wireless communications

In this paper, a novel compact CPW-fed slot small antenna was designed and fabricated on high-resistivity silicon （HR-Si） by micro-electronics process. The results of simulation are consistent with results of measurement for the antenna. The mode of the antenna is vertical and horizontal bidirectional radiations. The gain of antenna is 2.5 dB, and the resonance frequency approximately is 3 GHz. This fabrication can be compatible with antenna integration and CMOS process. The parameters of this antenna are for reference radar antenna system of Unmanned Aerial Vehicles （UAV）, satellite transmission, and communication.     

Parasitic effects of the metallic towers on the characteristics of the broadcast antennas

In this article, we use a tool NEC (Numerical Electromagnetic Code) to model antenna on top of a tower structure. Simulation results for the parasitic effect of the tower on characteristics of broadcast DVB‐T (Digital Video Broadcasting Terrestrial) antenna such as input impedance, return loss, gain, front‐to‐back ratio and radiation patterns are reported. In addition, the effect of a nearby tower on antenna characteristics is studied. A 3D tower and broadband antenna in the UHF (470‐862) MHz band are constructed. The antenna works for both digital and analog TV with return loss (RL) ≥ 10 dB, fractional bandwidth of 87% and gain of 12.3 dBi at center frequency. The effective radiated power is calculated by mounting the antenna at each face of the tower to give a satisfactory coverage to a region around the antenna.     

Cross‐polarization in dual polarization switching antennas

This paper presents the effect of the interaction between the switch and the antenna parameters on the cross‐polarization of a dual polarization switching antenna. It is shown that the isolated antenna cross‐polarization combines with the isolation of the switch giving place to a degradation of the polarization purity of the combined dual polarization switching antenna. Analytical expressions for the combination of the switch isolation and the antenna cross‐polarization in the switched antenna element are given. Simulations and pattern measurements are presented. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

星间链路天线指向建模与仿真分析

星间链路天线指向的分析在卫星通信中非常重要.为了深入研究天线指向特性从而改善星间链路以及轨道构型的设计,通过仿真方法实现了星间天线指向的建模与分析.在介绍天线参数基础上,分析了天线方向图和天线指向模型.根据卫星是否同轨道面或同轨道高度,区别描述了4种不同情况下的天线指向特性.基于HLA/RTI构建了卫星网络仿真环境,通过建立由MEO、LEO卫星和地面站构成的仿真场景,对MEO卫星间链路和LEo/地面站与MEO卫星间链路的天线指向特性进行仿真,得出轨内和轨间星间链路在天线指向特性方面的差异,并提出对星间链路设计的建议.     

一种具有宽带双极化低散射特征的微带阵列天线

针对阵列天线宽带散射缩减设计进行研究,设计了一种基于无源对消技术的低散射阵列天线,该新型微带阵列天线在宽频带内具有双极化低雷达散射截面（RCS, Radar Cross Section）性能;对基于两种散射性能不同的单元组成阵列的RCS性能进行了理论研究,进行了单元的散射幅度和相位对阵列RCS的影响分析;提出了一种加载T型缝隙的新型微带天线结构,该单元结构的辐射性能与散射性能能够进行独立调控和综合优化,该单元与传统微带贴片单元具有相似的辐射特性,并可在宽频带（带内和带外）内与传统微带单元产生有效相位差;将传统微带单元和加载T型缝隙的新型微带单元组成4×4阵列天线,仿真结果表明,提出的阵列天线在3GHz～7GHz（相对带宽80%）频带内实现了同极化RCS缩减,在3.3GHz～7GHz（相对带宽71.8%）频带内实现了交叉极化RCS缩减,缩减峰值分别为16.3dB和36.3dB,带内RCS缩减均值分别为14.1dB 和17.6dB;与传统微带阵列天线相比,提出的阵列天线增益下降小于0.1dB;提出的微带阵列天线具有高效率辐射和宽频带双极化低散射性能,为低散射阵列天线设计提供了新的思路。     

RFID tag antenna for ultra and super high frequency band applications

A novel dual‐band antenna for radio frequency identification tag is proposed for ultra high frequency (UHF: 915 MHz) and super high frequency (SHF: 2450 MHz) bands. The proposed tag antenna is a single sided dual‐antenna structure, designed on the grounded (metallic) dielectric substrate. The proposed tag antenna can be used on any kind of surfaces including metals without severe performance degradation due to its metallic ground plane. At UHF band, proposed tag antenna works as dual‐antenna structure. In the dual‐antenna structure, one antenna works for receiving and another for backscattering. Due to separate backscatterer, the maximum differential radar cross section improved and results in the enhancement of the maximum read range. Whereas at SHF band, proposed antenna works as conventional single antenna structure and during operations it switches between receiving and backscattering modes. The proposed antenna consists of a meandered line antenna and a rectangular patch antenna loaded with an F‐shaped and an inverted L‐shaped slots. The S‐parameters are measured by means of differential probe technique. Simulated and measured results are observed in good agreement. The read range is observed about 5 and 6 m at 915 and 2450 MHz, respectively. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:640–650, 2016.