共查询到18条相似文献,搜索用时 125 毫秒
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分析了非赋形双偏置天线产生椭圆波束的机理,将馈源的椭圆波束照射到轮廓线为椭圆形的付反射面上,通过双偏置天线的对称转换原理,主反射面产生椭圆波束.馈源波束由矩形口径的多模喇叭产生,它提供了等化的方向图.给出了馈源及天线的方向图计算公式.实验结果表明,实测方向图基本与理论计算一致.与其他类型的椭圆波束天线相比,本天线加工简单,同时天线效率也较高. 相似文献
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分析宽频带、双极化、恒束宽四脊喇叭的混合方法 总被引:10,自引:3,他引:7
介绍了作为反射面天线馈源的宽频带、双极化、恒波束四脊喇叭,运用有限元和模式匹配相结合的混合法详细且计算了四脊喇叭的广义散射矩阵。然后运用口面积分计算了四脊喇叭的辐射远场,给出了四脊喇叭和用四脊喇叭做馈源的反射面天线的实测结果。 相似文献
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《电子科技文摘》2002,(8)
0215340·光纤的偏振模色散及测量〔刊〕/唐月刀广播与电视技术一2002,29(3).一54一158(L) 02 15346伏拉索夫模式变换器数值计算〔刊〕/袁成卫刀国防科技大学学报一2002,24(2)一106一110(K) 0215341分析宽频带、双极化、恒束宽四脊喇叭的混合方法〔刊〕/何山红//电波科学学报一2002,17(2)一160一165(L) 介绍了作为反射面夭线馈源的宽频带、双极化、恒波束四脊喇叭,运用有限元和模式匹配相结合的混合法详细推导且计算了四脊喇叭的广义散射矩阵。然后运用口面积分计算了四脊喇叭的辐射远场,给出了四脊喇叭和用四脊喇叭做馈源的反射面天线的… 相似文献
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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。 相似文献
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提出了四喇叭单脉冲抛物面天线和多波束抛物面天线共用一个抛物面来提高四喇叭单脉冲抛物面天线的搜索性能。计算了个实例,该多波束抛物面天线的波束扫描角达22.78°、口径直径为53.33λ(λ=0.03 m)、馈源方向图为cosθ、增益比原四喇叭和波束下降4 dB左右。 相似文献
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Shaoyong Wang Qi Zhu Shanjia Xu 《Journal of Infrared, Millimeter and Terahertz Waves》2007,28(7):513-519
Design of a novel compact millimeter-wave microstrip antenna with wide bandwidth and broad beamwidth is presented. In the structure, multiple layers and a parasitic element as well as a coupling aperture are used to achieve wideband, while a conducting cylinder and the coupling aperture are used to obtain broad beamwidth. Finally, phased array with eight present elements has been designed as an example. Compared to traditional microstrip antennas and arrays, present antenna and array are of smaller dimension and broader beamwidth as well as wider bandwidth. 相似文献
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《Antennas and Propagation, IEEE Transactions on》2008,56(7):1908-1918
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Calculations are carried out with regard to the aperture illumination efficiency, spillover efficiency, and blockage efficiency of a shaped Cassegrainian antenna system whose feed pattern is not similar to that for which the antenna was designed. It appears that a maximum overall efficiency may be expected for antenna systems with a feed pattern having a slightly narrower beamwidth than those for which the systems were originally designed. It is further proved that the radiation pattern of mismatched systems is very unfavorable in the case of the beamwidth of the feed pattern being wider than the beamwidth of the feed pattern for which the system was designed. This is due to overillumination of the edges. 相似文献
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A one-parameter circular aperture distribution is developed which provides an optimum compromise between narrow beamwidth, low sidelobes, and low apertureQ . The pattern is a modifiedJ_{1}(x)/x , analogous to the Taylor one-parameter modified sin(x)/x line source distribution. Sidelobe envelope taper is essentially that of a uniformly excited circular aperture; hence the aperture is lowQ . The aperture distribution which is rotationally symmetric is given by a modified Bessel function of zero order. Like all high efficiency distributions, it has a pedestal. All antenna quantities, sidelobe ratio, beamwidth, aperture efficiency, and edge taper, are uniquely related to the parameterH . A table of these quantities is given for sidelobe ratios up to 50 dB. A typical pattern and several distributions are graphed. This new distribution allows tradeoff studies to be made against any design quantity, with all other quantities determined through the one-parameter. 相似文献
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A wide bandwidth and wide beamwidth L-probe-fed patch antenna array with a novel design of grounded structure is proposed and tested. The antenna is made of stacked patches supported by plastic screws. The patches are proximity fed via L-shaped probe. By cutting slots in two vertical side walls of a box-shaped grounded structure, an impedance bandwidth larger than 20% (SWR<1.5), an H-plane beamwidth over 90/spl deg/, and much reduction in backlobe radiation can be obtained. Details of the proposed antenna, simulation, and experimental results are presented and discussed. 相似文献
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TheE -plane beamwidth of a small pyramidal horn can be substantially reduced by the addition of paxabolic cylinder flanges of the proper focal length. Analysis of this antenna involves both geometrical diffraction theory and conventional aperture techniques. In the numerical and experimental examples chosen the flanges halve the half-power beamwidth without severe bandwidth reduction. Consequently a lightweight compact horn is achieved. 相似文献
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An aperture illumination compatible with the use of an even number of adjacent beam ports in a multiple beam feed network is discussed. The antenna pattern characteristics of near-in sidelobe levels, half-power beamwidth, aperture efficiency, and feed network loss are evaluated. Maximization of the available antenna gain at adjacent beam crossover points is shown to be possible for either sequential or simultaneons operation of a receiving system. The results presented indicate that lossy feed networks are quite suitable for certain array antenna applications. 相似文献
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Li-Chung Chang T. Burnside W.D. 《Antennas and Propagation, IEEE Transactions on》2000,48(12):1848-1857
A novel stable beamwidth, ultrawide-bandwidth low-scattering antenna is presented. This antenna is a modified version of the conducting slotline bowtie hybrid (SBH) antenna with resistive sheets (Rcards) introduced into the guiding structure design. Since the resistive sheets can attenuate creeping wave fields, much smaller rolled edges are needed in the Rcard SBH antenna. Moreover, due to the Rcard's partially transparent nature with respect to electromagnetic fields, the radar cross section (RCS) associated with this new antenna is smaller than the original conducting rolled edge one. By employing an optimization process based on the concept of the genetic algorithm, one can easily design the Rcard SBH antenna to obtain a very stable antenna beamwidth and phase center in both the E- and H-planes across the entire operating frequency bandwidth. Because of its constant beamwidth, low RCS, and broad-band features, the Rcard SBH antenna is an ideal antenna for many applications such as a compact range feed. Calculated and measured results are presented to demonstrate the performance of this new antenna 相似文献