一种X波段多极化椭圆波纹喇叭设计

针对当反射面天线大宽高比并要求多极化转换时，宜选择椭圆波纹喇叭作为馈源的需求，在详细研究径向槽波纹喇叭天线设计方法的基础上，采用波纹槽深渐变的方法，利用HFSS软件设计一种X频段椭圆率大于2的带正交模的椭圆波纹喇叭。实测结果表明，该喇叭具有驻波低、交叉极化抑制度高和良好的双极化波瓣等化性等优点，可满足多极化反射面天线对馈源的需求，具有较高的工程应用价值。     

偏置天线低交叉极化技术

本文在进一步分析偏置天线交叉极化与偏置角度焦径比关系的基础上，采用较小偏置角设计，大大地改善了单偏置天线的交叉极化。在相对于主极化峰值１－ｄＢ波束范围内优于－３０ｄＢ；并讨论子馈源交叉极化对整个天线系统交叉极化的影响。     

偏置抛物面反射器天线:述评

<正> Ⅰ.引言偏置抛物面反射器的主要优缺点偏置抛物面反射器不论址在结构上,还是在分析上都很复杂,其主要优点是:(1)降低了口径遮挡影响,如图1所示;(2)能把反射器对初级馈源的反作用减至最小。其缺点是:当被线极化初级馈源照射时,偏置反射器在天线辐射场内产生交叉极化分量;当使用园极化时,虽不产生交叉极化分量,但使天线波束偏离电轴。对于小的偏置反射器,在线极化情况下,也能观测到这种偏置影响。     

双频段共用圆锥波纹喇叭的设计研究

本文详细地研究了双频段共用圆锥波纹喇叭的设计方法,特别是模转换器的设计。文章还讨论了这类馈源交叉极化的计算和控制措施。     

小口径大张角波纹喇叭的优良设计

给出了接近60°的半张角波纹喇叭的设计实例及其设计程序,研究了它的4个槽的功能及参数。据此设计的小口径大张角波纹喇叭具有优良的E、H面等化方向图,优良的电压驻波比特性,优良的交叉极化性能,可作为前馈抛物面天线的馈源和标准喇叭。     

利用馈源的高次模改善偏置抛物面天线的交叉极化性能

提出了一种改进单偏置抛物面天线交叉极化特性的新方法, 研制出一种双模工作的新型馈源,分析了其工作原理,并进行了实验研 究,测试结果表明这种方法是可行的。     

全欧通信卫星上的小巧低交叉极化波纹馈源

引言欧洲空间局计划在八十年代发射的全欧通信卫星,将为欧洲提供高质量的区域通信。天线的基本结构是一个偏置的抛物面反射器,它在11—14千兆赫频段内发送或接收双线极化或圆极化信号。偏置反射器对线极化引起的去极化,可用一个“匹配馈源”来补偿。该馈源可使馈源辐射口径上的切向电场和非对称反射器焦平面场匹配。在这类馈源中由HE_(11)和HE_(21)模的适当迭加获得匹配场。     

波纹圆锥喇叭近场辐射特性分析

过去，预估圆锥波纹喇叭的辐射特性的理论分析仅运用于远场，但大多数副面却位于波纹喇叭的近场区域。本文用球面模展开方法（ＳＥＭ）探讨波纹圆锥喇叭在近场区域内的幅、相图形，并与实测值取得较好的一致性。应用该法设计高性能１８ｍ微波Ｃ波段４／６ＧＨｚ偏置天线所用小型化馈源中的圆锥波纹喇叭，在驻波系数、Ｅ／Ｈ面等化性、交叉极化等性能参数方面均获得较满意的结果。     

新分析方法计算馈源喇叭

利用场匹配法及平面波角谱法,采用圆波导的TE_(In)和TM_(In)模分析了馈源喇叭的散射矩阵,即“S”参量,详细地导出了S参量的表示式,并由“S”参量计算了馈源的驻波比与辐射场,得到了与实验较为吻合的结果;本文所提出的方法其优点在于它避免了求特征方程的特征根,从而避免了繁琐的数学计算,并可用以进行波纹喇叭的优化设计。     

一种Ka频段超低交叉极化宽频带波纹喇叭天线

波纹喇叭天线是一种结构紧凑、具有良好辐射性能的馈源天线,特别是轴向槽波纹喇叭天线可以在宽频段内实现极低的交叉极化,对扩展工作频段、实现极化复用有重要的价值。文章对轴向槽波纹喇叭天线的设计方法进行了研究,利用模式匹配法和全波算法软件设计了一种Ka频段超低交叉极化宽频带轴向槽波纹喇叭天线。实测数据表明,该喇叭天线工作频段可覆盖整个Ka频段（26.5~40 GHz）,在频段内回波损耗小于-20 dB、交叉极化小于-45 dB,同时天线具备良好的方向图对称性和相位中心稳定性,在卫星通信领域具有广阔的应用前景。     

宽频带双极化低副瓣偏馈抛物面天线

介绍了一种宽频带双极化低副瓣天线的设计、加工方法和测试结果。采用馈源偏置的方法来减小副瓣,采用波纹喇叭实现天线双极化的要求,并且采用双椭圆切割抛物面来增加天线的效率和减小方位主波束宽度。天线的理论分析与实验结果吻合较好,优于所需的技术指标要求。     

Radiating Mechanisms in a Reflector Antenna System

The radiating mechanisms of a reflector antenna system are discussed. Means of computing the various component fields are given, including aperture radiation, direct feed radiation, and diffracted radiation. An offset parabolic reflector antenna system fed with a corrugated horn is treated as an example. Means of reduction of the undesired components of radiation are suggested.     

3300mm口径W波段辐射计偏馈反射面天线设计

本文为W波段辐射计设计了一副口径为300mm偏馈反射面天线,天线要求的工作频率为94.5GHz,副瓣电平低于-25dB,交叉极化电平低于-30dB,半功率波束宽度优于1?。文中采用较小偏置角以改善偏置天线的交叉极化特性,采用焦面场匹配法和模比利用法设计了匹配馈源,通过仿真优化设计,得到良好的波瓣等化电平和驻波比。测量结果表明,测量值与理论值吻合,满足辐射计的指标要求。     

Application of rectangular and elliptical dielcore feed horns toelliptical reflector antennas

The pattern characteristics of elliptical reflector antennas are investigated when they are fed by rectangular and elliptical horns partially filled with a dielectric. The bandwidth characteristics of these dielcore horns are superior to those of their corrugated horn counterparts. Representative reflector patterns are computed to properly demonstrate the utility of these feeds for reflector antennas with elliptical apertures. This reflector antenna exhibits high efficiency and low cross polarization, and may be suitable for radar and satellite antenna applications. The antenna configuration may become useful in relatively small antennas where more than 10% cross-polar bandwidth is required. The efficient dielcore horns may also be used as feeds for elliptical nonshaped dual-reflector antennas     

Optimizing multimode horn feed arrays for offset reflector antennasusing a constrained minimization algorithm to reduce cross polarization

This letter presents an algorithm for suppressing the cross polarization of single offset reflector antennas illuminated by a cluster of multimode horn feeds using a constrained minimization routine. The design variables are the mode ratios for the higher order modes excited in the feeds relative to the dominant TE₁₁ mode. The goal is to systematically determine the optimum mode ratios such that the overall crosspole performance of the reflector antenna improves relative to the single TE₁₁ mode excitation. The multimode horns considered are Potter-type (dual mode) horns and trimode horns     

Radiation and depolarization of multibeam offset reflectors fed bymultimode pyramidal horns

The depolarization contents of the radiating currents on the surface of a multibeam offset parabola are minimized, for different beams, using multimode pyramidal horn feeds. Small percentages of the TE ₁₁ and TE₂₀ modes are used, respectively, for vertical and horizontal polarizations, in combination with the fundamental TE₁₀ mode. The mixture ratio increases for feeds with higher pointing angles to the reflector surface. Additionally, the beams that are away from the symmetry plane, suffer changes in the polarization bearing angles, which increase for further beams. Far radiated fields are computed from the depolarization minimized reflector currents, using both the orthogonal components of the linear polarization, for a 3M offset reflector with a diameter-to-focal-length ratio of unity, at 4 GHz. Minimized depolarization levels of around -40 dB for vertical polarization, and of around -34 dB for horizontal polarization are found. The linearly and circularly polarized diagonal horn feeds yield symmetric pencil beams. Their polarization, however, is quite high and difficult to control for linear polarization. For circular polarization, to the contrary, the depolarization is quite low     

Design of multiple-edge blinders for large horn reflector antennas

Attaching blinders to the sides of pyramidal horn reflector antennas and other large aperture antennas is one method of controlling high sidelobes for horizontal polarization. This paper describes analysis and design procedures for arriving at a useful multiple-edge blinder for reducing undesirable sidelobes of a pyramidal horn reflector antenna. Several blinders have been designed and tested for use with a pyramidal horn reflector antenna. They are directed at reducing a high sidelobe near90degin the azimuth plane where levels (referred to the main lobe) of -52 dB at 3.74 GHz and -58 dB at 6.325 GHz are presently typical. A 14-edge blinder designed using these techniques reduced these levels by 20 dB at 3.74 GHz and 12 dB at 6.325 GHz and did not significantly degrade antenna performance for other angles and other polarizations.     

Paraboloidal reflector offset fed with a corrugated conical horn

A paraboloidal reflector, offset fed with a corrugated conical horn, has been examined as a possible antenna for use in millimeter wave communications systems when minimization of interference is an important consideration. Low far-out and back-lobe radiation were primary objectives. Experimentally obtained data, representative of performance at 37 GHz, is presented. When appropriately shielded to limit spillover, levels more than 75 dB below the main beam maximum have been obtained in the far-out and back-lobe regions.     

用于空间功率合成的线阵馈电焦散抛物曲面天线

提出了一种用于空间功率合成的焦散抛物曲面天线,该反射面天线是由xoz平面的一条抛物线沿着yoz平面上的另一条抛物线正交扫描所形成的,天线用8单元E面喇叭线阵进行偏馈。研究了天线的反射面结构参数对天线性能的影响以及横向偏焦电扫描特性,给出了不同辐射方向下阵列的相位配置公式。仿真和实验结果表明:提出的方案可以在给定方向合成高增益波束,与同样线阵馈电的抛物柱面天线相比,H面3dB波束宽度从8.2°下降到了5°,天线增益提高了2.2dB.     

基于介质波导混合模式的双频馈源喇叭天线

随着大型反射面天线技术的不断发展,天线系统对设备功能的多样化与一体化提出了更高的要求,馈源作为大型反射面天线的核心,其性能决定了反射面天线整体特性。文章基于介质波导混合模式提出了一种介质加载双频馈源喇叭天线,工作于X(7.25~7.75 GHz) / Ka(21~22 GHz)频段。利用特征值理论求解双层介质波导中电磁场表达式,通过改变双层介质波导拓扑结构,形成表面波态的混合模式HE₁₁。在X频段由于喇叭口径小,形成了E面H面等化的方向图;在Ka频段,通过改变介质锥形状,形成类似点源辐射,也形成了E面H面等化、交叉极化低的方向图。对该馈源进行加工并测试,测试方向图与仿真结果较为吻合。将该馈源应用于卫星地面接收系统的13 m环焦反射面天线,经验证,该天线在工作频段口面效率均≥60%。