一种双频双圆极化微带天线的设计

提出了一种仅利用单端口馈电的共口径双频双圆极化微带天线。天线通过在对应高端谐振频率的圆形贴片外层附加对应低端谐振频率的圆环形贴片,并采用四个窄带条连接两贴片,从而实现双频工作;通过在圆形和圆环形贴片外侧开缺口的方式实现了圆极化波辐射,并通过在两贴片上开置的缺口相正交,从而形成了低端右旋圆极化（RHCP）、高端左旋圆极化（LHCP）的特性。对提出的天线进行了仿真并优化设计,给出了该天线在两个谐振频段上具有较好的阻抗匹配和双圆极化性能。     

一种高隔离度双频MIMO天线

文中设计一种具有高隔离度的双频MIMO天线。将两款宽带毫米波天线垂直正交地放置于FR-4介质基板上,得到结构紧凑的双端口极化分集天线和四端口MIMO天线,利用其相互正交的极化方式提高了相邻端口间的隔离度。为了满足双频特性,分别在两天线单元的辐射贴片上刻蚀半圆环形和U形缝隙,地面开了长方形槽。通过HFSS仿真分析表明,所设计的天线可工作在28 GHz(24.5～29 GHz)和39 GHz(36～47 GHz),且在工作频段内具有较好的辐射特性,相邻端口间的隔离度达到了30 dB以上。同时,在天线上方加载了4根金属条作为引向器,提高了天线的增益。     

一种双频双圆极化微带天线的设计

极化复用是提高通信容量和系统抗干扰能力的一种有效手段。天线同时辐射两个极化的电磁波才能够支持极化复用。文章提出了一种双频段微带天线,能够同时辐射两种圆极化波。天线利用单馈电法实现圆极化,利用双层贴片堆叠实现双频工作。文章最后利用三维电磁仿真软件,对微带天线进行了仿真验证,仿真结果表明该天线满足双频双圆极化性能。     

一种双频双圆极化层叠结构微带天线的设计

对一种新型的双频双圆极化微带贴片天线进行了研究,该天线可发射L波段的左旋圆极化信号,接收S波段的右旋圆极化信号。天线采用双馈点馈电的层叠结构,利用宽带功分移相器设计馈电网络,为双馈点提供双圆极化所需的激励电流。贴片和馈电网络上附加短截线,通过调整短截线的长度,即可微调谐振频率,使得天线的调试十分方便,又提高了天线的收发隔离度。该天线结构简单,调试方便,为便携式卫星通信机提供了一种实用的小型化收发天线。     

新型共口径四频双圆极化微带天线的设计

提出了一种加载"牛角"形折线槽的贴片天线结构,通过调节折线槽尺寸,可灵活实现小频率比的双频设计。基于此设计了一种新型共口径四频双圆极化微带天线,仅利用三层堆叠结构实现了四个频段的覆盖,包括北斗三个频段B3(1 268±10)MHz、L(1 616±10)MHz、S(2 491±10)MHz和L波段的(1 995±10)MHz。仿真结果表明,天线在四个频段范围内均满足回波损耗小于–10 d B、轴比小于3 d B及基本的增益和波束宽度要求。天线两输入端口隔离度小于–15 d B,因此可用作北斗天线收发一体卫星通信终端应用。     

双频双圆极化北斗天线的设计

设计了一种的小型化的双频双圆极化微带天线。对两个工作于主模的正方形贴片,通过采用对角切角方法,在北斗卫星导航系统的S频段实现右圆极化。通过蚀刻不对称臂U型槽结构,在北斗卫星导航系统的L频段实现左圆极化与小型化。其相比对普通的圆极化天线尺寸减小了24%,使用HFSS进行仿真,仿真结果表明本天线可以达到北斗系统对天线的各项指标要求。     

一种单层贴片式双频双极化滤波天线

设计了一种单层式跨频段双频双极化滤波天线。该天线在同一平面上的高频低频辐射贴片共用一个馈电端口,且均可以在两个垂直方向馈电实现交叉方向的线极化辐射。该天线通过在馈电点与低频辐射贴片之间插入一个低通滤波器,明显提高了高频辐射贴片的交叉极化隔离度。研究结果表明,带滤波结构的天线在两个频率点的反射系数小于-20 dB,4.9 GHz的最大增益大于4.8 dBi,26 GHz的最大增益11.7 dBi,〖JP2〗两个辐射频率的辐射方向图均体现良好的线极化特性,且主极化比交叉极化大20 dBi。该天线可作为未来微波与毫米波共用的5G通信终端天线或5G通信基站的MIMO天线阵元,相关技术和结论对于研制一体化集成的双频交叉极化相控阵天线也有重要参考价值。     

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。     

缝隙加载H形双频天线

为了适应现代双频通信系统的要求,双频天线必须具有小尺寸和频率易调节的特点.通过在H形微带天线的辐射边附近采用U形缝隙加载,在单层微带天线上实现了双频效果.和常规的双频微带贴片天线相比,该天线的尺寸可以大大减小.通过改变天线的尺寸参数,高频段和低频段可以很容易地调节,本设计中得到频率比范围是1.716～2.363.该天线在两个频段有相同的极化平面和较宽的辐射波束.     

可收拢展开的宽带双圆极化柔性薄膜天线

星载相控阵雷达因其平台的特殊性要求其天线具有大型轻质、可收拢展开的特点。设计了一种可收拢展开的宽带双圆极化柔性薄膜天线。天线各层均采用柔性薄膜材料制作,相邻层间为空气,因此天线整体为柔性可收拢展开。采用两相互垂直的"H"形缝隙和双层微带贴片结构,并结合3 dB电桥实现了宽带和高隔离度的双圆极化。仿真和测试结果表明,该薄膜天线单元两馈电端口驻波小于2的相对带宽约为36%,极化隔离度大于32 dB,并给出了天线单元双圆极化波瓣方向图的测试结果,其3 dB波瓣宽度为64°,天线单元增益为6.2 dB,并设计了天线小阵。     

Dual-band and dual-polarised horn antenna including conical helix

A horn antenna having dual-band and dual-polarisation operation is proposed. To implement a small-sized structure providing circular polarisations in the Ka- and K-band, the antenna is designed using the horn radiator on the basis of a conical helix which is exited by two ports for TX and RX in both ends. Through a design optimisation process, a compact dual-band and dual-polarised horn antenna having high gain and high isolation performance was realised     

New Proximity Coupled Feeding Method for Reconfigurable Circularly Polarized Microstrip Ring Antennas

A new simple single-feed method for circularly polarized ring antennas has been investigated. Experimental and theoretical investigation show that either right-handed (RH) or left-handed (LP) circular polarization (CP) can be easily achieved by selecting one of the two input ports of the antennas. The proposed U-shaped microstrip feed line excites the fundamental ${rm TM}_{11}$ mode of the ring radiating elements through proximity coupling along the semi-annular section of the line. The induced rotating surface currents on the ring radiators contribute to the circular polarization behavior of the antennas. Two types of rings have been investigated. Square ring prototypes operate at 2.7 GHz have been designed, fabricated and evaluated to show the basic operating principles of the antennas, while annular ring radiating elements operate at 2.255 GHz are realized to demonstrate the reconfigurable capability of the new feeding structure. In the reconfigurable design, a high isolation RF switch is used to direct the input signal between the two input ports. With suitable biasing arrangement of the RF switch, the antenna is capable to radiate at either types of circular polarization. The reconfigurable design is fed by a single microstrip line. Return losses, axial ratios, gains and radiation patterns of the prototype antennas have been measured for verifications. A parametric study of the new feeding structures with a square ring has been carried out for important design guidelines.      

可用于物联网的高隔离度双频MIMO天线

设计了一种高隔离度双频多输入多输出（MIMO）天线,该天线覆盖2.4 GHz和5 GHz无线局域网频带,可以应用于移动物联网之中。天线包含两个相同的辐射单元天线,采用微带馈电的方式进行馈电。单元天线使用单极子天线作为基本辐射器,其包含一根长的和短的单极子天线,分别谐振在低频和高频频段。通过在两个单元天线中间加载T型隔离器提高了单元天线之间的隔离度。天线的辐射振子、馈电以及T型隔离器都印刷在同一块微波板材上,从而方便了天线的制作和加工。仿真结果表明,该天线在1.9~2.8 GHz以及4.7~6.2 GHz频带范围内能实现良好的双频工作特性,天线隔离度近20 dB,可以广泛应用于物联网系统中。     

一种提高微带MIMO 天线端口隔离度的新方法

多输入多输出(MIMO) 无线通信系统已经成为提高通信系统可靠性和数据传输速率的有效技术。MIMO 通信系统中,终端天线的性能对系统通信容量的提升至关重要。为了提高天线端口隔离度,提出了一种在微带天线辐射贴片上加载缝隙阵列实现天线极化分集,提高天线隔离度的方法,并且将这种方法应用于两个2 单元微带MIMO 天线设计中,取得了良好的效果。缝隙阵列加载不但抑制了微带MIMO 天线单元间的耦合,而且产生了更多谐振频点,改善了高频谐振频点畸变的天线辐射方向图,并且天线尺寸也得到了很大的减缩。最后对比分析了设计的两个微带MIMO 天线,实测结果与仿真计算比较可知,在工作带宽内,单元天线间耦合得到了非常有效的抑制。这种在平面天线辐射贴片加载缝隙阵列改变天线极化方向的技术可以很好地用来抑制多天线系统中单元天线间的耦合,而且对天线的其他性能不会造成影响。     

Dual-band circularly-polarized square microstrip antenna

New designs of obtaining dual-band circular polarization (CP) radiation of a single-feed square microstrip antenna are proposed and experimentally studied. The proposed single-feed dual-band CP designs are achieved by inserting four T-shaped slits at the patch edges or four Y-shaped slits at the patch corners of a square microstrip antenna. From experiments conducted, a patch size reduction as large as 36% for the proposed design, compared to a conventional CP design without the inserted slits, has been obtained. Details of the design considerations of the proposed antennas are described, and experimental results of the obtained dual-band CP performances are presented and discussed     

Reconfigurable dual-band circularly polarized microstrip patch antenna for wireless applications

A new design of reconfigurable single-feed circular patch microstrip antenna for dual-band circular polarization application is proposed. The dual-band functionality is realized through incorporating cross-slots of equal slot length in the circular patch and utilizing two PIN diodes to switch the slots on or off. A pairs of tuning stubs are used to tune the circular polarization performance. The design process is presented and good results were obtained.     

Novel slot spiral antenna designs for dual-band/multiband operation

New applications for wireless communications are typically accompanied by a need for antennas that integrate several frequencies and functionalities under a single aperture. Different requirements for pattern, gain, and polarization at each operating frequency further complicate the design of such antennas. Novel slot spiral antenna designs for dual-band/multiband operation are introduced. Typically excited to operate in the first mode, the proposed two-arm slot spiral is redesigned to operate efficiently in the second mode and in a hybrid first/second mode for better functionality. Several key features are introduced to achieve requirements for impedance matching, pattern, and gain suitable for a specific automotive dual-band DAB/SDARS (digital audio broadcasting/satellite digital audio radio services) antenna system. Among these features are new feeding systems, a suitable mix of spiral growth rates, and a low-loss spiral arm termination. The design is accomplished using full-wave finite-element boundary integral simulations and is verified with measurements.     

Low sidelobe precise beam aspect ratio scalar horns

A new design method for developing either linearly or circularly polarized low sidelobe corrugated sectoral horn antennas is described. These antennas may be designed to provide constant beam aspect ratios (BAR's) ranging from 2:1 to 5:1. Such performance is achieved over bandwidths of up to 21 percent for dual-linear polarization and 17 percent for circular polarization. Potential applications include use in communication satellite reflector systems where beam shaping, frequency reuse, or high adjacent beam isolation is required. Selecting aperture phase distribution rather than simply minimizing aperture phase error is the key to obtaining these results. Mechanical design and performance data are presented to facilitate fabrication of antennas that satisfy a wide range of performance requirements.     

一种新型双频宽波束四臂螺旋天线的设计

根据移动卫星通信和卫星导航定位中对天线宽波束、圆极化和低仰角增益等要求,设计了一种新型的双频四臂螺旋天线,通过将工作于不同频段的两副结构类似的天线以内外共轴的方式形成一个整体来实现双频工作。天线通过开槽线巴伦实现平衡馈电,利用四臂螺旋自身的结构特点构造了90°自相移结构,获得了较好的宽波束圆极化特性。测试结果表明。实测和仿真结果基本一致,天线在两个频段都实现了较好的宽波束圆极化特性。     

基于传输线模分析法的2G Hz矩形微带天线设计

在现代通信系统中,微带天线以其体积小、便于实现线极化或圆极化,并能很好的适用于双频工作的优点,被广泛的应用在2G移动通信通信系统中。本文采用传输线模分析法设计了一种适用于3G移动通信系统的2GHz矩形微带天线,并通过仿真及优化,改进了天线的增益和效率。