考虑馈源位置误差的面天线机电耦合优化设计

 针对面天线结构设计中存在的机电分离以及忽视馈源位置误差的问题,从机械电磁两场耦合的角度,将反射面天线主面误差和馈源位置误差统一到天线方向图的远场计算公式中,从而可以研究包含馈源支撑结构在内的天线结构参数对主要电性能（包括增益、副瓣、波瓣宽度、指向精度等）的影响。利用该公式建立了包含馈源支撑结构参数的天线整体机电耦合优化模型,通过某8米天线的仿真对比表明了该耦合优化模型的优点,最后将该优化模型应用于某40米大型反射面天线,取得了满意的效果。     

反射面天线遮挡效应的快速计算

在抛物面天线的设计过程中,馈源正馈时,馈源的遮挡效应是一个不容忽略的问题。文章在对遮挡因子分析的基础上,结合天线量化方向图的概念,给出了一种简化计算公式,可以用来估算遮挡对主瓣增益的影响;最后,使用仿真软件FEKO验证了公式的准确性。这一公式可以作为工程设计的依据,具有一定的使用价值。     

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。     

Aperture efficiency and line feed phase center of parabolic cylindrical reflector antenna

Formulas for calculation of the aperture efficiency of a parabolic cylindrical reflector antenna fed by a line feed along the focal line are presented. The efficiency is factorized into a number of subefficiencies which include contributions from line feed end diffraction, and from blockage and reflections from line feed supports and from diffraction by gaps in the reflector surface. One of the subefficiencies is used to define a phase center for the line feed as well as to obtain a formula for calculating it.     

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。     

超宽带馈源技术发展综述

反射面天线是最主要的高增益天线形式,在与无线电相关的各个领域具有广泛应用。随着科技的发展,对于超宽带(UWB)反射面天线的要求日益迫切。因此,作为反射面天线核心的馈源,如何在超宽的频带内具有良好的阻抗特性、恒定的辐射特性和稳定的相位中心,已成为当今天线技术的研究热点。给出了超宽带馈源的设计要点,总结了超宽带馈源的类型、特点和发展现状,并对超宽带馈源设计技术的未来提出了展望。     

用FDTD和物理光学混合法分析毫米波抛物面天线

抛物面天线通常的分析方法是几何光学法和物理光学法,对于电大尺寸的抛物面天线这两种方法都可以得到较好的结果,对于电小尺寸馈源的抛物面天线,馈源方向图不仅取决于辐射器本身的辐射特性,其馈电结构对馈源方向图也有较大的影响,在此情况下,用上述方法得到的结果与实验结果之间有较大的误差.利用FDTD可以把整个馈电结构纳入计算域中,得到辐射器完整的近区场,由等效原理可求出抛物面上电流分布,从而用物理光学方法计算抛物面天线远区场.本文用这种混合方法分析计算了毫米波波导裂缝作为辐射器的抛物面天线,计算结果和测试结果相当吻合,证明了方法的有效性.     

一种双频喇叭馈源的相位中心分析

多模圆锥喇叭天线是一种应用较广的高效率喇叭天线,它被广泛应用于反射面初级馈源。双频多模圆锥喇叭天线在收发两个频率处的相位中心是不重合的,当其作为反射面馈源时,其相位中心及安放位置的确定对于反射面天线的性能有着不可忽视的影响。从天线相位中心的定义出发,计算了双频多模喇叭天线在收发频率处的相位中心,并对该天线在偏置反射面系统中的安放位置进行了分析,确定了馈源的最佳安放位置。     

Pattern synthesis of the offset reflector antenna system with lesscomplicated phased array feed

The performance degradation of an offset reflector antenna with off-axis scanning feed and distorted reflector surface can be improved by using a phased array feed. Generally, both analog attenuators and phase shifters are used in phased array feed. Yet, it seems to make the feed system very complicated. In this paper, a phase-only gradient search (POGS) algorithm is developed to optimize the performance of offset reflector antenna systems using phased array feed that is equipped with phase shifters only. This technique not only can greatly simplify the complexity of phased array feed, but also can provide the reflector antenna with better antenna gain and sidelobe level control capability. Simulation and experimental results are presented to illustrate the excellent performance of offset reflector, with limited beam scanning capability, can be obtained by using this less complicated phased array feed     

部分为凿孔表面的反射器天线等效反射系数及噪温的计算

采用等效馈源及凿孔表面的反射与传输系数导出了部分为凿孔表面的反射器天线等效反射系数及天线噪声温度的计算公式。计算表明对于部分为网状表面（25m直径以外）的40m天线，只要孔的直径（圆孔）或边长（方孔）约为十分之一波长，即使部分网面的孔积率达到70％，反射面等效反射系数近似于1，而引入的附加噪温约为零K。     

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...     

Synthesis of multireflector antennas by kinematic and dynamic raytracing

A technique for synthesizing reflector surfaces that transform a known input ray-field (e.g., the radiation field of a feed) to a desired output ray-field (e.g. an aperture distribution) is presented. The synthesis problem is reduced to solving linear equations by local biparabolic expansions of the reflector surfaces. Because the solution is easier to control, this is advantageous compared to existing techniques based on solving nonlinear differential equations. The condition to obtain low cross polarization can therefore be readily included, and the requirements for an exact solution to exist can be found clearly. The latter has been the subject of discussion in the literature for several years. The synthesis technique is applied to a shaped-offset dual-reflector antenna and to the proposed dual-reflector feed of the spherical reflector antenna in Arecibo. In both cases circular and elliptical apertures are considered     

G/T maximization of a paraboloidal reflector fed by a dipole-diskantenna with ring by using the multiple-reflection approach and themoment method

A 1.8-m paraboloidal reflector fed by a dipole-disk antenna with a beamforming ring is optimized for high G/T at L-band by using the moment method (MM) and the multiple reflection (MR) approach. The MR approach is based on using MM to calculate the radiation and scattering patterns of the feed, using physical optics plus uniform geometrical theory of diffraction (UTD) to include the reflector, and in addition to include the mutual interaction (multiple reflections) between the reflector and the feed by using the expression for the sum of an infinite geometric series. The MR approach is shown to be equally accurate as a MM solution of the complete antenna with reflector, provided the reflector is in the far field of the feed, and the MR approach is much faster. As a result of the calculations using the MR approach, design curves are presented showing how the G/T varies as a function of antenna geometry, size, and elevation angle, all for a given noise profile of the surrounding sky and ground. The computed radiation patterns and G/Ts are compared with measurements for several elevation angles and surrounding terrain     

Compact antenna test range without reflector edge treatment and RF anechoic chamber

There are several types of CATRs (compact antenna test ranges) used in antenna-pattern measurements. An offset reflector is generally used to generate the quiet zone of a CATR. Serrated edges, rolled edges, or R-cards are generally chosen along the reflector's edge to reduce the edge-diffraction field inside the quiet zone of the CATR. In order to reduce stray signals from the environment, a high-quality RF anechoic chamber is required for a CATR. In this paper, a new type of CATR, without either a reflector edge treatment or an RF anechoic chamber, is developed. A commercially available DBS (direct-broadcast satellite) reflector antenna, without edge treatment, is used as the reflector antenna of the CATR to generate the quiet zone of the antenna test range. In order to improve the quiet zone's performance, the fields due to feed spillover, edge diffractions, and other stray signals are gated out by the ITDAMS (impulse time-domain antenna measurement system). The RF interference in the environment can also be reduced by time synchronization and pulse integration of the impulse time-domain antenna measurement system. In order to verify the capabilities of the proposed CATR, three kinds of antennas (a low-directivity horn antenna, a high-directivity 60 cm direct-broadcast satellite reflector antenna, and a 25 cm Ka-band Cassegrain LMDS - local microwave distribution system - antenna) were measured by the proposed CATR. The antenna-pattern results agreed quite well with those of a near-field range and a far-field range.     

Ka 波段EBG 天线阵列的仿真与分析

电磁带隙(EBG)天线是一种可以提高天线辐射口径及增益的新型天线,本文首先以FSS 结构作为EBG 反射面,角 锥喇叭作为辐射源,设计了一种可以工作在29.7-30.2GHz,最大增益为23dB 的EBG 天线;其次,研究了7 个喇叭构成六 边形阵列时的阵列特性;最后,将EBG 天线用作单反射面多波束天线的馈源研究了波束的覆盖特性,结果表明,当波束 大小为1.12°时,多波束天线的峰值增益为44.5dB,边缘交叠电平为40.4dB,载干比大于12dB。证明了这种EBG 天线 具有良好的工作性能,为将来小型化反射面多波束天线的设计提供了一种新的思路。     

A shaped single reflector offset antenna with lowcross-polarization fed by a lens horn

A novel compact primary-fed offset reflector antenna with the potential of radiating circular as well as elliptical beams with low cross-polarization, is proposed. The reflector is fed by a horn with a phase-correcting lens in the aperture. Compared to the dual-reflector offset antenna, the concept is easier to assemble and mechanically more robust. The antenna has been synthesized and analyzed by computer programs resulting from modifications of corresponding PO programs for dual-reflector offset antennas. The synthesized antenna exhibits similar cross-polarization, side-lobe level, and aperture efficiency as those of dual-reflector offset antennas, although the one-to-one correspondence between zero cross-polarization and conformal mapping from the feed to the aperture, is not exactly valid for this approach     

A magnetic current loop array in a reflector antenna

A magnetic current loop antenna array is designed, implemented, and measured. Radiation pattern, input impedance, and efficiency of the array are presented. The array is intended as a feed in a reflector antenna. Using a 360 mm solid dish, the overall gain of the reflector antenna is 24.6 dB at 9 GHz. The tolerance in placing the feed at the focal point of the dish is high. The present feed is low cost, self-supportive, robust, and easy to manufacture. It is an ideal substitute for the horn in a TVRO or VSAT antenna     

反射面天线焦面场采样研究与相控阵馈源设计

为了设计高性能的相控阵馈源(phased array feed,PAF),通过反射面天线焦面场最优采样的研究,给出了PAF参数与天线口径效率之间的关系,总结了PAF的最优采样范围和单元间距,导出了PAF单元数量的计算公式.给出了一个9 m天线的PAF设计实例和性能分析,在4～7 GHz频率范围内,扫描范围为±3°时,天...     

Millimeter-wave double-dipole antennas for high-gain integratedreflector illumination

A double-dipole antenna backed by a ground plane has been fabricated for submillimeter wavelengths. The double-dipole antenna is integrated on a thin dielectric membrane with a planar detector at its center. Measured feed patterns at 246 GHz agree well with theory and demonstrate a rotationally symmetric pattern with high coupling efficiency to Gaussian beams. The input impedance is around 50 Ω and will match well to a Schottky diode or SIS detector. The double-dipole antenna served as the feed for a small machined parabolic reflector. The integrated reflector had a measured gain of 37 dB at 119 μm. This makes the double-dipole antenna ideally suited as a feed for high-resolution tracking or for long-focal-length Cassegrain antenna systems     

一种新型的介质反射面天线

提出了一种新型的多层介质结构的反射面天线，反射平面上所需要的相位补偿通过选择合适的介质厚度来实现，使用几个多层圆形介质即可满足条件。与传统的高增益天线相比，该结构设计简单，加工方便。验证了几种不同层数的结构和一个等口径的抛物面反射面天线。加工并测试了一个采用Vivaldi做馈源的4层结构的反射面天线。仿真和测试结果均表明该天线具有良好性能。