Antel天线的基本应用

天线的方向性系数和增益 天线的方向性系数(Directive Factor)和增益(Gain)是选用天线的最主要参数之一。天线增益被定义为天线最大方向性增益与天线效率的乘积。天线的射束宽度(Beamwidth)是指在天线垂直面(电场E面)或水平面(磁场H面)方向性图主波瓣上，其幅度比主瓣峰值低3dB的两点之间的加角角度。     

基于共形馈电网络的新型双频四臂螺旋天线

针对卫星地面手持终端系统对天线高效率宽波瓣的应用要求,文章提出一种新型双频印刷一体化四臂螺旋天线结构,通过两种方式提高其双频辐射效率:第一,每组辐射振子分成两个支路,分别以不同的长度、宽度和螺旋角度绕制以减少振子间耦合,同时覆盖两个不同的频点;第二,馈电网络和辐射振子进行一体化设计,提高其馈电效率。测试结果表明:在两个间距很近的频点(1.1倍频程)能够分别实现4.3dBi(低频)和4.2dBi(高频)的右旋圆极化增益,且4dBi以上右旋圆极化增益相对频带宽度分别为6%(低频)和5%(高频),圆极化3dB波瓣宽度均达到130°以上。该天线的双频点、宽波束、高效率性能适合于卫星通信手持终端系统应用。     

一种介质埋藏异形微带八木天线的设计

为达到某重点项目性能要求,综合运用微带天线、八木天线和介质埋藏天线理论及设计方法,设计出了一种介质埋藏异形微带八木天线. 该天线将传统八木天线的引向振子由一个改变为两个,形成“￥”形,用来规划波束方向和形成双波束;在天线贴片两旁增加“栅栏”,聚集了电磁波的辐射,提高了天线增益,同时还获得了较大的相对阻抗带宽. 测试表明:在Ku频段的一中心频率上,其绝对带宽为1.9 GHz,最大增益为3.92 dB;在E面具有两个主波瓣,θ=15°处波瓣宽度为11°,θ=347°处波瓣宽度为10°. 所设计天线在性能和功能上均满足项目需求,对该项目中信号的接收和发射起到了关键作用. 此外,该天线在其他通信、侦察和干扰等场合也具有广阔的应用价值.     

基于遗传算法的非对称多波束反射阵天线设计

针对传统方法设计的多波束反射阵天线增益低、波束偏移大、要求波束对称等问题,通过引入全局优化算法中的遗传算法对反射阵相位分布进行优化,以完成非对称多波束反射阵天线设计。为验证其有效性,设计并制作了一副Ku频段,波束指向分别为θ1=25°,1=0°和θ2=15°,2=180°的非对称双波束反射阵天线。测试和仿真结果较吻合,天线在中心频点的增益为26.03dBi,效率达到28.04%,1dB增益带宽和3dB轴比带宽均能覆盖11.3~12.3GHz(8.3%),实测波束指向为θ1=24.3°,1=0°和θ2=15°,2=180°,波束偏移0.7°。结果表明遗传算法能有效完成非对称多波束反射阵天线设计。     

77 GHz汽车角雷达宽波束平坦增益阵列天线设计

设计了一款基于波束赋形技术的宽波束、平坦增益平面阵列天线,用于汽车角雷达系统. 该阵列天线由三个1×10串馈线阵组成,串馈线阵采用单元不等间距分布的Dolph-Chebyshev天线综合法进行设计以降低副瓣. 为了满足汽车角雷达宽视场角（field of view,FOV）的需求,对平面阵列天线采用波束赋形技术以展宽方位面的波束宽度并提高增益的平坦度. 仿真与实测结果吻合较好,实测结果表明1×10线阵副瓣电平为?19.7 dB;3×10平面阵列天线的方位面3 dB波束宽度为106.4°,方位面增益平坦度可达?45°~45°,其最大增益为11.3 dBi.     

基于开口谐振环的高温超导超增益天线的研究

针对空间天线在移动通信中的应用，设计了一款适用于空间应用的高温超导超增益天线。采用开口谐振环结构，通过类似于八木天线的方式排列以实现天线的高增益，使用超导材料代替传统金属材料降低天线的损耗。仿真结果表明该天线工作在2.45 GHz,增益为7.29 dBi,实验测得天线增益为7 dBi,比哈林顿定义的相同尺寸的天线增益高2.01 dB。该天线具有小型化和高增益的特点，天线尺寸为22 mm×34 mm×0.5 mm。     

一种波瓣等化的多波束龙伯透镜天线

基于3D打印技术设计、制造了一种具有波瓣等化特性的工作在X波段的多波束龙伯透镜天线。透镜所需梯度变化的相对介电常数通过改变透镜每个单元的介质填充率得到。运用一组双模圆锥喇叭天线作为馈源,从而产生具有波瓣等化特性的多个波束。实验证明,该天线能够在三维空间产生多个波束,在水平和俯仰方向覆盖±20o的范围,各波束辐射特性几乎相同。天线的最高增益为22 dBi,3 dB波束宽度为8o,具有高增益和良好的聚焦特性。由于该天线制造简单、快速且成本低,凭借其良好的工作特性,在雷达、探测、传感等领域有着良好的应用前景。     

一种用于卫星定位系统的宽波束圆极化天线

在卫星通信、定位设备中,为了迅速完成定位和通信功能,一般要求天线具有较大的波瓣宽度和较好的低仰角增益.研究设计了一种具有良好低仰角增益的宽波束圆极化四臂螺旋天线,该天线在上半空间的增益分布十分均匀,10°仰角的增益相对峰值增益下降不超过 3dB.为了改善天线的轴比性能,提出了一种4臂等幅、相位依次相差 90°馈电的天线方案,仿真结果表明,这种天线的增益特性和轴比特性都得到了较大的改善.     

用太阳源测量UHF频段50 m天线增益及误差分析

简述了利用太阳源测量天线增益的基本公式,讨论了各种修正因子的计算方法.当50 m天线工作于611 MHz时,测量的天线增益为47.754 dBi,天线效率为58.25%,且测量的天线增益同理论增益吻合很好.最后,对增益测量误差进行了分析,其均方根误差小于或等于±0.29 dB.     

左手材料在线极化微带贴片天线上的应用

为了实现提高天微带天线增益,减小天线波瓣宽度的目的,利用左手材料的零折射率特性,对线极化微带天线进行了增加覆盖层的处理.对由色散稳定的左手介质结构单元用组成的覆盖层进行了结构仿真优化.测量结果表明使用左手材料覆盖层后天线波瓣减小了8°,增益提高了1.8 dB.     

A Design and Analysis of Dolph-Chebyshev Microstrip Planar Array Using Butler Matrix Beamforming Networks

1　IntroductionInrecentyears,personalandmobilecellularcommunicationhasexperiencedanoverwhelmingin creaseinthenumberofusers,leadingtothehugeexpansionofcellularcommunicationsystems.Theproblemsassociatedwiththeearlyusedomnidirec tionalantennasincellularcommunicationbasesta tionsarepartlysolvedbyusingsectoredantennasorcellsectorization ;thatissplittingupa 360°areainto3or 6individualsectorsormore .Thetransmittedpowerisstillnotefficientlyutilizedbecausethean tennabeamsarestillfixedindirectionanddon…     

低互耦星载相控阵天线设计

介绍了一款工作于Ku频段的低互耦星载相控阵天线的设计方法, 采用在阵列单元周围加载金属腔体的方式降低阵列单元之间的互耦效应, 从而改善相控阵天线的方向图扫描特性.针对相控阵天线在二维±60°范围内低副瓣波束扫描的特点, 对5×5子阵和16×16阵列进行了研究, 验证了阵列的互耦降低方法的有效性和电性能.研究结果表明:相控阵单元间互耦小于-16 dB, 而相控阵单元在15.1~16.8 GHz电压驻波比小于2, 相对带宽11%;在频率为f₀±500 MHz范围内, E面3 dB波束宽度大于98°, 5 dB波束宽度大于113°, H面3 dB波束宽度大于113°, 5 dB波束宽度大于122°.在仿真设计的基础上, 研制了子阵天线试验样机, 测试结果与设计结果吻合良好, 证明了降低互耦方法的有效性, 天线单元方向图满足在±60°范围内波束扫描的要求, 可应用于相控阵雷达系统.     

Beam steerable square loop antenna over hybrid high impedance surface

A novel hybrid high impedance surface is presented and a beam steerable four feed square loop antenna is built on this structure. At a test frequency of 4.7 GHz, the proposed hybrid high impedance surface based square loop antenna is 4.69 mm high and has an impedance bandwidth of 650 MHz and directivity of 8.7 dBi. Compared with the earlier reported steerable square loop antenna the new antenna s performance equates to a thickness reduction of 61, bandwidth enhancement of 150 , a directivity improvement of 2 dBi, a co-polar sidelobe reduction of 11 dB, and a cross-polarisation sidelobe reduction of 5 dB.     

Piezoelectric transducer controlled multiple beam phased array using microstrip Rotman lens

A simple and low-cost multiple beam phased array is designed using a microstrip Rotman lens and multi-line phase shifter controlled by a piezoelectric transducer (PET) at Ka-band. A microstrip Rotman lens with five beam ports and nine array ports is used as a feed for a multiple beam antenna array to generate five beams centered at the angles of 0/spl deg/, /spl plusmn/15/spl deg/, and /spl plusmn/30/spl deg/. The lens fed nine-element patch array shows the antenna gain of 10 dBi and sidelobe suppression of 10 dB. Each beam is steered over /spl plusmn/8/spl deg/ using two PET-controlled phase shifters, and the five beams cover /spl plusmn/38/spl deg/ from the broadside.     

A planar slot array with four independent beams

Active Doppler velocity sensors require an antenna system that generates three or more independent beams. A four-port dual-mode antenna that generates four independent beams from a single aperture is described. The signals emanating from the four ports generate four beams in space through a common aperture of crossed slot radiators. Isolation between the four signals processed through the antenna is obtained primarily by utilizing the mode isolation that exists between theTE_{10}andTE_{01}modes in square waveguide. The isolation obtained between ports was 27.5 dB or greater. The special design problems and the effect of dimensional tolerances on the port isolation are discussed. A gain of greater than 30 dB for each beam and an overall antenna efficiency of approximately 71 percent were achieved. The beam pointing directions ranged from 27 to 29 degrees from the normal to the aperture. Sidelobes of 15 dB or better were also obtained.     

Dual Band Planar Spiral Feed Backed by a Stepped Ground Plane Cavity for Satellite Boresight Reference Antenna Applications

This paper presents development of a new planar spiral feed for a satellite boresight reference antenna, operating at two widely separated frequency bands (2200–2300 MHz and 8000–8400 MHz). A stepped ground plane cavity with different quarter wavelength distances is proposed to provide unidirectional patterns at these frequency bands. A back lobe suppression of around 12 dB in 2 GHz band and better than 15 dB in 8 GHz band with a measured on-axis axial ratio of less than 3 dB is achieved for the dual band planar spiral feed with stepped ground plane cavity configuration. A boresight reflector antenna employing this feed has measured beamwidths of 7 degrees and 1.8 degrees respectively and gain of 26 dBi and 36 dBi at 2250 MHz and 8200 MHz.      

Dual polarised multibeam antenna

A dual polarised four-beam antenna array for the 1850-1990 MHz frequency band is presented. The polarisations are ±45° to vertical. The antenna has eight inputs corresponding to two orthogonal polarisations and four beams. The return loss and cross-polar isolation for a single Butler beam exceeds 15 and 22 dB, respectively. The radiation pattern is similar to an ideal Butler pattern and the cross-polarisation level is <-21 dB in the beams     

均匀照射赋形反射面天线设计

为提高反射面天线的照射均匀性，利用波束赋形技术设计一款工作在15 GHz的高性能偏置反射面天线.该天线由一个非均匀有理B样条（non-uniform rational B-splines，NURBS）反射面和一个介质棒馈源组成，NURBS反射面通过物理光学法结合Nelder-Mead优化算法来赋形，从而获得理想的天线辐射场.仿真结果表明，赋形后的反射面天线相对旁瓣电平低于-20 dB，增益在-2.7°~2.7°的波束范围内超过20 dBi，且浮动不超过1 dB.该天线具有结构简单、旁瓣低、增益均匀的特点，在卫星通信等领域具有重要作用.     

使用非均匀特异媒质覆层的高增益谐振腔天线

采用非均匀特异媒质覆层,设计了一种具有高增益特性的新型谐振腔天线。该谐振腔天线采用矩形微带贴片天线作为辐射单元,安装在金属谐振腔内,其谐振频率为10 GHz。为提高天线增益,将腔表面安装蚀刻在微带基板上,由周期性单元组成特异媒质覆层。迥异于常规的单元尺寸均匀一致特异媒质覆层,本文研制的非均匀特异媒质覆层包含9×9个矩形单元,单元大小渐变。仿真表明,与常规均匀特异媒质覆层相比,该新颖的非均匀特异媒质覆层相当大程度提升了天线定向辐射性能：天线增益提高1.2 dB(从20.3 dBi增加到21.5 dBi),天线的旁瓣得到了抑制,主旁瓣比下降5 dB;同时,天线谐振频率和阻抗带宽等其他性能基本保持不变。