一种快速稳健的致密焦面阵列馈源设计方法

致密焦面阵列馈源(DFPAF)融合了多喇叭多波束馈源和相控阵列馈源(PAF)的特点,与多喇叭多波束馈源和常规相控阵列馈源相比较,它可以同时提供更多的固定赋形波束进一步拓宽视场。在射电天文、雷达、电子侦察和卫星通信等领域引起了极大的关注。由于其阵列结构与常规阵列馈源不同,导致设计方法也具有特殊性,因此近年来展开了对其设计方法的研究。该文充分利用反射面天线的固有特性,并结合阵列天线理论,提出一种可以快速、稳健地设计致密焦面阵列馈源的方法,给出了设计原理和设计结果,并和最具代表性的多喇叭多波束馈源进行了性能对比分析,为设计致密焦面阵列馈电的大型反射面提供理论和数据参考。     

基于阻抗超表面的高效率角锥喇叭馈源

研究了一种基于阻抗超表面的高效率角锥喇叭馈源.将阻抗超表面放置于金属角锥喇叭内壁, 获得了一种性能良好的新形式高效率馈源.首先分析了超表面对表面阻抗特性的调控作用, 并证明该超表面对TE波和TM波呈现不同的阻抗特性.在特定的阻抗条件下, 该喇叭内壁可以支持平衡混合模式, 从而获得旋转对称的辐射波束.然后设计和加工了Ku频段的超表面高效率馈源, 馈源的测试方向图表明其辐射性能优良.最后将该馈源照射一款1.25 m Ku频段环焦天线, 测试其辐射方向图, 同样显示出其优异性能.与该环焦天线原有的波纹喇叭馈源相比, 超表面高效率馈源的性能与波纹喇叭馈源相当, 同时在体积、重量和成本方面具有明显优势.     

周期结构馈源阵对多波束天线性能的影响

具有周期结构的馈源阵能够最大化实现馈源的共用,并且能够用相干耦合周期结构?波束形成网络(CORPS?BFN)实现.通过设计一种双模圆锥喇叭,按照一定规律进行排布组成馈源阵,结合CORPS?BFN设计思想,得出各馈源阵中每个喇叭的激励系数并进行仿真分析,从而得出与单个馈源相比,周期结构馈源阵能够降低多波束天线副瓣电平的结论.     

卫星便携站馈源喇叭天线的研究和设计

对卫星便携站的馈源喇叭进行了研究,并设计了一款新结构的介质加载馈源喇叭天线,以替代该卫星便携站原有的波纹喇叭馈源。该介质加载馈源喇叭天线的特点是结构简单、组装简易、成本低廉。通过比较和分析,该天线具有增益高、反射小、交叉极化低、波束对称及波瓣尖锐的优点,尤其是天线的口径效率最高可达到95.7%。可见介质加载馈源喇叭非常适用于卫星便携站的馈源以及卡塞格伦天线的初级辐射器。     

反射面天线馈源喇叭边缘照射电平的分析

反射面天线设计的关键就是通过选择合适的喇叭馈源边缘照射电平以追求天线的高性能（增益,旁瓣电平, 效率等）。本文主要利用实例验证了标准反射面天线馈源喇叭的优选边缘照射电平,分析了赋形反射天线馈源喇叭的优选 边缘照射电平,给出了标准反射面和赋形反射面在设计中各自馈源喇叭的优选边缘照射电平。从而可以在设计工作中对 于不同形式的反射面天线有针对性的设计馈源喇叭的边缘照射电平。     

Ku、Ka频段龙伯透镜馈源阵列技术研究

针对卫星通信中龙伯透镜天线不同频段的馈源并排放置导致最大波束指向的偏移,无法实现多频段馈源上、下行跟踪同一颗卫星,提出了馈源阵列馈电的方法。通过辐射口面采用介质杆天线取代喇叭以改进馈源,此方法减小了馈源的阵间距,利于馈源组阵。结果表明:利用馈源组阵技术可以解决波束偏焦问题,实现多频段收发同一颗卫星的目的,同时也分析了阵列馈源馈电对天线增益和效率的影响。     

单脉冲雷达多模馈源分析与设计

详细分析了单脉冲雷达四喇叭三模馈源的原理和设计方法,指出馈源模比的变化和口径面相位分布的不一致,都会对馈源的方向图产生影响,考虑这些因素,经过严格推导,得出了这种馈源方向图的完整解析表达式。利用该结果,分析频率和模比对馈源方向图的影响,设计最优的馈源模比,计算出理想的馈源的和差方向图。并进一步对馈源的相位中心进行了分析,给出了频率和喇叭1：7面的相位分布对相位中心的影响结果。这些都会对工程设计具有一定的指导意义。     

一体化馈源大角度扫描折叠式反射阵列天线

卫星通讯服务的快速增长催生了对于“动中通”设备旺盛的需求.由于具有低剖面、加工方便、功能实现多样等特点, 折叠式反射阵列具有应用于“动中通”系统的巨大潜力.针对这一应用需求, 提出了一种具有大角度扫描能力的折叠式反射阵列设计方案, 基于多层印刷电路板(Printed Circuit Board, PCB)技术,设计了一种工作在C波段可用于折叠式反射阵列具有60°扫描能力的微带缝隙单元, 利用该单元设计了0°、45°和60°波束指向的固定波束折叠式反射阵列.此外, 使用阵列馈源替代传统喇叭馈源, 完成了馈源与主反射面的一体化设计, 实现了折叠式反射阵列天线结构的平面化.固定波束折叠式反射阵列的仿真和实测结果表明在4.85~5.15 GHz的频率范围内, 阵列具有60°波束扫描的能力.     

一种新型宽频带双极化馈源的设计

高效率的宽频带馈源可以大大减少馈源数量,减小天线口径,在天线工程中应用很广。采用正方形振子形式设计的新型宽频带双极化馈源,与传统馈源相比,该馈源具有频带宽、体积小以及波束等化好等优点。首先给出了这种馈源的几何结构和腔体理论分析,并对这种馈源反射腔的几种不同结构形式进行了对比分析,分析结果表明采用圆形反射腔形式是最佳选择。对比仿真分析和理论计算结果,两者非常吻合,验证了理论分析的正确性。     

超宽带双馈源反射面天线

比幅测角具有原理简单,工程易实现的特点[1].天线沿轴向对称放置的双馈源常采用喇叭、振子等形式.然而对于倍频程带宽的超宽带情况,普通喇叭、振子天线很难满足波束相交电平要求.本文分析了超宽带工作下馈源的偏焦特性及双馈源的相对位置关系,并结合仿真和实验设计了大张角对数周期天线来作为馈源,在倍频程上实现波束相交电平近似一致的双波束.     

A dual doubly curved reflector antenna having good circular polarization characteristics

A new type of shaped-beam radar antenna having good polarization characteristics is described. This antenna is composed of a dual doubly curved reflector system and a feed horn with good axial ratio, such as a dual-mode horn. The rotationally symmetrical beam of the feed horn can be converted into a shaped beam by the reflector system without degradation of the axial ratio. The design of this type antenna is discussed and the experimental results of a model antenna with a cosecant squared beam are shown. Integrated cancellation ratio of the model was 22 dB.     

S/Ka双频段馈源新型喇叭罩设计

论述了一般喇叭罩的设计原则和思路,提出了采用B夹层结构的聚四氟乙烯S/Ka双频段馈源喇叭罩的设计思想,及喇叭罩的具体设计方法.实验证明,该喇叭罩性能优良,已成功应用到某大型S/Ka双频段工程中.     

A High Performance 700?GHz Feed Horn

We present a design of a high performance horn operating at 700 GHz. The feed, which comprises three smooth-walled conical sections, is easy to machine and yet has comparable performance to a corrugated horn. The measured radiation patterns show high main beam circularity, low sidelobe level and good agreement with theoretical predictions. The cross-polar level is below −20 dB across a frequency bandwidth of 140 GHz. The new design allows the fabrication of high performance, large format feed arrays cheaply and rapidly.     

Optimization of an Offset Receiver Optics for Radio Telescopes

The latest generation of Cassegrain radio astronomy antennas is designed for multiple frequency bands with receivers for individual bands offset from the antenna axis. The offset feed arrangement typically has two focusing elements in the form of ellipsoidal mirrors in the optical path between the feed horn and the antenna focus. This arrangement aligns the beam from the offset feed horn to illuminate the subreflector. The additional focusing elements increase the number of design variables, namely the distances between the horn aperture and the first mirror and that between the two mirrors, and their focal lengths. There are a huge number of possible combinations of these four variables in which the optics system can take on. The design aim is to seek the combination that will give the optimum antenna efficiency, not only at the centre frequency of the particular band but also across its bandwidth. To pick the optimum combination of the variables, it requires working through, by computational mean, a continuum range of variable values at different frequencies which will fit the optics system within the allocated physical space. Physical optics (PO) is a common technique used in optics design. However, due to the repeated iteration of the huge number of computation involved, the use of PO is not feasible. We present a procedure based on using multimode Gaussian optics to pick the optimum design and using PO for final verification of the system performance. The best antenna efficiency is achieved when the beam illuminating the subreflector is truncated with the optimum edge taper. The optimization procedure uses the beam’s edge taper at the subreflector as the iteration target. The band 6 receiver optics design for the Atacama Large Millimetre Array (ALMA) antenna is used to illustrate the optimization procedure.     

Design and analysis of quasi-integrated horn antennas formillimeter and submillimeter-wave applications

The authors present a systematic process for the design of multimode quasi-integrated horn antennas, and provide a full range of practical antenna designs for millimeter- and submillimeter-wave applications. The design methodology is based on the Gaussian beam approach and the structures are optimized for achieving maximum fundamental Gaussian coupling efficiency. For this purpose, a hybrid technique is used in which the integrated part of the antennas is treated using full-wave analysis, whereas the machined part is treated using an approximate model. This results in a simple and efficient design process. The design procedure has been applied to the design of 20-, 23-, and 25-dB quasi-integrated horn antennas, all with a Gaussian coupling efficiency exceeding 97%. The designed antennas have been tested and characterized using both full-wave analysis and 91/370-GHz measurements. The quasi-integrated horn antennas are also examined as feed elements for Cassegrain antenna systems and are proved to be comparable to the traditional machined corrugated horn feeds     

Gaussian beam techniques for illuminating reflector antennas

Simple design procedures are presented for use when a Gaussian beam is used to illuminate a classical reflector antenna. Displacement of the location of the beamwaist toward the focusing element in the case of electrically small antennas where the aperture is in the near field of the feed was calculated together with modification of the required beamwaist radius. Dual reflector antennas were discussed and design procedures appropriate for systems with large and small focal length to diameter ratio developed. Cases where a reflector or subreflector is electrically small, or in the near field of a feed, are readily treated. For elliptical beam antennas, a simple illumination system using only a scalar horn and a single cylindrical lens can generally be found; this has no ray optics analogue. A configuration of this type is discussed, with a practical case study of a 28-by-80-λ elliptical Cassegrain antenna operating at a wavelength of 3 mm. The design process for designing the feed system is discussed in detail. Despite the small size and relatively large aperture blockage, an aperture efficiency of 0.48 was measured, which compared quite well with the expected efficiency of 0.53, thus verifying the validity of the Gaussian beam design approach     

一种高效率的四脊喇叭馈源

以天线口径效率为目标,研究了四脊喇叭口径对馈源波束等化、波束宽度恒定和天线口径效率等性能的影响,得到了一种3∶1带宽高效率圆四脊喇叭馈源的设计。该馈源在整个频带内具有较低的电压驻波比,三个主平面的主极化方向图波束等化较好,-10d B波束宽度基本恒定,且天线口径效率达到55%以上。     

一种T形太赫兹成像系统的设计

为了获得较高的帧速率以及降低成本,提出了一种带有波束扫描功能的T形太赫兹成像系统.系统包含两个共极化扇形波束扫描天线,它们以T字形正交摆放.收发天线具有基本相同的内部结构,由角锥喇叭馈源、产生扇形波束的椭圆主反射体以及用于实现波束扫描功能的旋转次反射体构成,而所有这些元件都镶嵌在两个平行金属板之间.给出了T形太赫兹成像系统的具体设计,提出了设计高性能扇形波束扫描天线的系统化方法,最后给出了一些实验的成像结果,以论证系统的功能.     

The hexagonal horn as an efficient Gaussian beam launcher

A new type of feed horn-the hexagonal horn-is proposed and investigated by means of Gaussian-Hermite beam-mode analysis. The electric-field distribution at the horn aperture plane is approximated. The polarization efficiency is 88.66%. The fractional power in the fundamental beam mode is about 85%. The near- and far-field radiation patterns are calculated. The high fractional power in the fundamental beam mode of the horn indicates that it can be used as an efficient Gaussian beam launcher in quasi-optical systems