宽带正交模耦合器的设计

宽带天线技术的发展对天线馈源的宽带性能提出了更高的要求。作为实现双极化天线馈源的关键器件,正交模耦合器(Orthomode Transducer,OMT)的宽带性能将直接影响宽带天线馈源的性能。为扩展OMT的工作带宽,设计了工作在Ka波段的宽带OMT。该OMT结构新颖,能实现优良的驻波特性和极化隔离特性。应用HFSS对进行了优化设计,工作带宽可达42%,回波损耗优于-20 dB,通带内端口隔离优于-50 dB。     

基于口面场方法的W波段高口面效率单脉冲卡塞格伦天线（英文）

提出来一种应用于直升机防撞雷达的高口面效率W波段单脉冲双反射面卡塞格伦天线.口面分析方法的提出解决了W波段反射面天线口面相位分布不均匀的缺陷,从而有效地提高了口面的利用效率.利用该方法,本文研究并制作了口径为135 mm、焦距为40.5 mm的W波段卡赛格伦天线,并且设计了由四个E面多缝隙电桥和四个四分之一波导波长延迟线级联构成的和差网络.经测试,该单脉冲天线在93 GHz具有38.6 dBi的和波束增益,相应的口面效率为54.7%;差波束的零深优于-22 dB,副瓣电平小于-18 dB.测试结果与基于口面分析方法的仿真结果吻合,从而证明了本文所研究天线可以应用于高口面效率的W波段单脉冲系统中.     

基于Turnstile结构的超宽带正交模耦合器研究

正交模耦合器是反射面天线馈源系统中非常重要的无源器件,正交模耦合器的带宽决定了天线的工作带宽,其性能直接影响接收机的性能。为满足新疆天文台Q波段(30~50 GHz)制冷接收机的需求,描述了Turnstile结构的正交模耦合器,公共端口为圆波导,2个分支端口为标准矩形波导。应用电磁仿真软件HFSS对正交模耦合器进行了设计与优化。仿真结果表明,在50%相对带宽内,回波损耗优于-22 d B,正交隔离度优于-46 d B。为进一步开展毫米波宽带OMT的研究提供了理论设计基础。     

基于口面场方法的W波段高口面效率单脉冲卡塞格伦天线

本文提出来一种应用于直升机防撞雷达的高口面效率W波段单脉冲双反射面卡塞格伦天线。口面分析方法的提出解决了W波段反射面天线口面相位分布不均匀的缺陷,从而有效的提高了口面的利用效率。利用该方法,本文研究并制作了口径为135mm、焦距为40.5mm的W波段卡赛格伦天线,并且设计了由四个E面多缝隙电桥和四个四分之一波导波长延迟线级联构成的和差网络。经测试,该单脉冲天线在93GHz具有38.6dBi的和波束增益,相应的口面效率为54.7%;差波束的零深优于-22dB,副瓣电平小于-18dB。测试结果与基于口面分析方法的仿真结果吻合,从而证明了本文所研究天线可以应用于高口面效率的W波段单脉冲系统中。     

双频段双极化共孔径阵列馈源反射面天线设计

介绍了一种新型Ku/Ka双频段双极化共孔径阵列馈源偏馈抛物柱反射面天线的设计。在双频段双极化共孔径阵列馈源设计中,Ka波段采用裂缝波导阵,并且位于共孔径馈源阵列的下层,双极化Ku波段采用微带贴片天线、位于共孔径阵列馈源的上层。文中给出了该双频段双极化共孔径阵列馈源的设计及测试结果,并将该测试结果代入偏馈抛物柱反射面天线中在FEKO软件平台上进行了半实物仿真,仿真结果表明,该双频段双极化共孔径阵列馈源偏馈抛物柱反射天线实现了如下设计目标:Ku波段双极化水平面扫描范围为±17°,两个主面副瓣电平优于-30dB,Ka波段水平面扫描范围为±10°,两个主面的副瓣电平优于-30dB,双频段双极化两个主面的波瓣宽度和波束指向完全匹配。     

一种宽带四脊波导正交模极化耦合器

坐落于贵州天然喀斯特地形的500 米口径球面射电望远镜(FAST),其低噪声接收机系统需要高性能正交模极化耦合器,对此,提出了一种四脊波导形式宽带正交模极化耦合器快速有效的设计方法:首先分别设计四脊波导正交模极化耦合器的两个关键部分,然后进行整体优化,为了改善带内阻抗匹配性能可以在同轴输出端口的内探针引入阶梯匹配环。使用这种方法研制的FAST L 波段极化器工作带宽达到2 颐1,在整个带宽范围内极化器的反射系数小于-20 dB,极化耦合水平低于-43 dB,带内插入损耗优于0. 15 dB,仿真和实测结果有很好的一致性。提出的设计方法适用于各种频率范围的宽带四脊波导正交模极化耦合器的设计。     

一种C波段宽带正交模耦合器设计

正交模耦合器是实现天馈系统双极化的关键部位，适用于雷达探测、电子对抗以及无线通讯系统等多个领域。本文设计了一款Boifot型的C波段宽带正交模耦合器，通过垂直极化通路和水平极化通路的独立仿真，阐述了正交模耦合器工作带宽的扩展方法和工作原理。结果表明，在其工作频段43%的相对带宽内，回波损耗小于-20 dB，传输损耗小于0.07 dB，端口隔离度优于-57 dB，交叉极化水平低于-60 dB，实现了宽带低损耗高隔离的良好性能。     

Ka波段膜片加载曲线内壁矩形喇叭天线

介绍一种工作在Ka波段曲线内壁矩形喇叭天线,这种天线的辐射结构采用高斯曲线构成的曲面矩形喇叭,在曲面矩形喇叭口加载金属膜片,通过对天线参数的设计优化,在22.5～26.5 GHz频带上方向系数大于15 dB,驻波比优于1.8,E面方向上副瓣电平比主瓣低26 dB以上,对比标准增益角锥喇叭天线测试显示,膜片加载曲面喇叭体积小,改善了传统角锥喇叭的3 dB波束宽度,降低副瓣,结构简单,活动方便,可单做馈源亦可做反射面天线馈源。     

宽频带低轴比双圆极化波导阵列天线设计

基于波导损耗小、易加工等特点,设计了一种应用于卫星通信系统的新型X波段宽频带低轴比双圆极化波导阵列天线。采用平面方形喇叭阵列、正交模耦合器和波导窄边耦合功分器来实现双圆极化的工作方式。据此设计,加工了一套16×16单元天线阵列,尺寸大小为440mm×440mm×50mm。采用电磁仿真软件Ansoft HFSS进行仿真设计,详细介绍了该天线的设计方法,测试结果和仿真结果吻合良好。测试结果表明,该天线在12%的工作频段内轴比优于1.5dB,驻波比优于1.6,带内增益大于31.0dB,天线辐射效率优于80%。     

基于BΦifot结构的双脊波导超宽带正交模耦合器设计

射电天文望远镜的发展对天线馈源的宽带性提出了更高的要求,作为实现双极化天线馈源系统的关键器件,正交模耦合器的宽带性能将直接影响宽带天线的性能。分析了双脊波导厚度对于水平/垂直极化波的影响,使用电磁仿真软件HFSS对水平/垂直极化波模式进行分析,对7 mm波段(30~50 GHz)的正交模耦合器进行了设计与优化,在50%相对带宽内,回波损耗优于-21 d B,正交隔离度优于-50 d B,为进一步开展毫米波宽带OMT的研究提供理论设计基础。     

A novel lightweight dual-frequency dual-polarized sixteen-element stacked patch microstrip array antenna for soil-moisture and sea-surface-salinity missions

The main motivation for this paper is to discuss the development of a novel compact and light-weight dual-frequency, dual linearly polarized, high-efficiency, stacked-patch microstrip-array antenna for use in standalone aircraft-based remote sensing applications. Results from simulation, fabrication, and testing of a sixteen-element stacked-patch array antenna, optimized for an L-band frequency of operation, are presented. The design center frequencies were 1.26 GHz and 1.413 GHz with 10 MHz and 25 MHz bandwidths in each band, respectively. Due to the large number of design parameters and demanding design requirements of beam-efficiency, sidelobe levels, and polarization characteristics, particle-swarm optimization (PSO) and finite-difference time-domain (FDTD) simulations were used for synthesis and analysis. Cancellation techniques, based on symmetry, were applied to the antenna ports, with a custom-built feed network to reduce cross polarization. Simulations and measurement results from a spherical near-field test facility confirmed excellent performance of the array configuration, with a beam efficiency of greater than 90%, isolation better than -35 dB, and cross polarization in the main beam of the array better than -40 dB. From the sixteen-element array simulations and experimental verifications, one of the objectives of the present study is to suggest the possibility of using customized dual-frequency, dual-polarized arrays as potential feeds for reflectors to replace the traditionally used conical horns for future soil-moisture and sea-salinity missions     

L/S双频段圆形阵列单脉冲抛物面天线

该文研究了一种以六单元圆形阵列作为照射器的单脉冲抛物面天线,这种天线具有实现宽频带跟踪的独特优点,其输出信号类似于圆波导单口径多模馈源,具有一个和波束,一个锥形差波束,并给出了没有接收机参与的情况下,将宽频带的和差两个通道变成单通道的途径。研制了一套L(1#61485;2GHz),S(2.2#61485;2.3GHz)宽频带双圆极化单通道单脉冲天线,对该天线的照射器、分波器、波束形成网络、单通道变换器等组件和馈源结构集成化设计进行比较详细的介绍。该馈源安装到一个3.2m的抛物面上,频率为1.1GHz,2.2GHz时,和波束增益分别为22.9dB,30.1dB;差波束零深为35dB,40dB。在L/S两个频段内跟踪稳定。     

Single- and dual-polarized millimeter-wave slot-ring antennas

Single- and dual-polarized dielectric lens-supported slot-ring antennas have been developed for operation at millimeter-wave frequencies. The antennas are fed with a coplanar waveguide (CPW) to be compatible with uniplanar mixers and low-noise amplifiers, and the feedline is shown to have a minimal effect on the antenna performance. The measured antenna patterns agree well with theoretical results and have symmetric main beams, low sidelobe levels (<-15 dB), low cross polarization (<-20 dB), and 27 dB directivity. A 2×2 array of single-polarized slot-ring antennas for monopulse applications demonstrates excellent patterns at 94 GHz with -3 dB crossover power levels in both elevation and azimuth scans. The dual-polarized slot ring antenna patterns are nearly identical to those of the single-polarized antenna, and two-port isolation is as low as -25 dB. The dielectric lens-supported slot-ring antenna is an excellent candidate for compact, low-cost millimeter-wave systems with fixed or variable polarization capabilities     

Dual-polarized slot-coupled patch antennas on Duroid with teflonlenses for 76.5-GHz automotive radar systems

A dual-polarized 76.5-GHz microstrip patch and teflon lens antenna system was designed, constructed, and tested. A receiver (RX) array of three dual-polarized microstrip patches was coupled through a 10-cm-diameter lens to produce radiation patterns with 3° beamwidths and beam crossovers of -3 dB. The transmitter (TX) consisted of a single dual-polarized microstrip patch coupled through a 2.5-cm-diameter lens to produce a 10° beamwidth. Slot-coupled patches were used to isolate the microstrip feed circuit from the radiating elements. The antennas and feeds were fabricated on commercially available 5880 Duriod substrates. Cross-polarization levels were less than -20 dB and were typically less than -30 dB over the entire beam at the design frequency. First sidelobe levels were no greater than -15 dB and were typically closer to -20 dB. Stepped and unstepped versions of the 10-cm-diameter receive lens were designed and fabricated. Antenna system sidelobes levels were lower with the stepped lens while the cross-polarization levels were comparable     

高端口隔离度双极化贴片天线设计

针对WLAN的MIMO系统应用要求,并缩小天线所占据的空间,设计具有高端口隔离度的双极化贴片天线。采用共面带状线馈电的环形贴片和微带馈电单极贴片相结合形式,利用环形辐射元与单极子辐射元产生正交线极化的特点,实现双馈双极化天线。实验结果显示,所设计天线的工作频带范围为2.27~2.73GHz,端口隔离度在31dB以上。同时,单极结构辐射元主极化要比其交叉极化大25dB以上,环形结构辐射元在较大空间范围内其主极化比交叉极化大23dB以上。这表明所设计双馈双极化天线具有较高的端口隔离度,且有良好的极化纯度。通过结构参数调整,还可望同时覆盖5.8GHz频段,以满足IEEE802.11n标准要求。     

双频共面单脉冲天线研制

论述了双频共面单脉冲天线的设计方法。天线口径较小时,馈源的遮挡口径相对较大,这对天线的性能影响很大,选择口径较小的双频馈源是实现双频共面的关键。天线低频段馈源采用4喇叭单脉冲形式,高频段馈源采用单口多模单脉冲喇叭,通过各自的馈电网络实现单脉冲功能。天线采用卡塞格伦形式,通过对天线和馈源的优化设计,可实现天线双频段工作性能,实测结果与计算结果基本吻合。     

并行角馈双极化微带天线阵的分析与设计

本文提出利用双端口的并行角馈实现双极化天线,并设计了一种新的双极化馈线网络。综合运用了多端口网络模型、腔模理论、分片法和补片法,给出了各天线单元和双极化馈线网络的理论分析方法。实际设计了一副6GHz频段的单层共面的四元天线阵,实测的双端口隔离度达-50dB,其性能明显优越于通常的单层双极化微带天线阵列。     

一种倾斜波束双极化天线

提出了一种具有倾斜波束辐射特性的新型双极化天线。该双极化天线由两个正交的纺锤形偶极子 组成,根据准八木天线原理,在偶极子两侧加载寄生振子作为反射器和引向器,用以实现倾斜波束辐射。这种纺锤 形偶极子可以增加电流长度从而减小天线的整体尺寸。同时在每个偶极子贴片上蚀刻两个梯形槽,以实现良好的 阻抗匹配。另外,通过连接到同轴线的金属短截线对纺锤形偶极子进行激励,简化了天线馈电结构。测试结果表 明,天线的阻抗带宽为3. 36~3. 69 GHz(S11 <-10 dB),两个极化端口之间的隔离度大于16 dB,波束倾斜度为30°,波 瓣宽度约为85°,可适用于单侧大角度扫描阵列。     

Dual-polarized dielectric resonator antennas

Two high input-isolation dual-polarized dielectric resonator (DR) antennas are presented in this communication. First, a slot-coupled feed technique with two narrow slots forming a "T" configuration is employed to design a dual-polarized DR antenna. Input isolation exceeding 35 dB has been obtained in the band for this design. Secondly, a hybrid feed mechanism with a coplanar waveguide (CPW) feed and a slot feed is used to achieve a dual-polarized DR antenna. A vertical strip is added at the center strip of the CPW feed to improve the coupling to the DR antenna. Also, input isolation exceeding 35 dB has been obtained in the band. Good cross-polarization levels less than -20 dB in the broadside direction are attained. The measured far-field radiation patterns are stable in the passband and the measured gains are around 5.5 dBi for the two feed ports of both cases.