共查询到18条相似文献,搜索用时 125 毫秒
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《红外与毫米波学报》2015,(6)
提出来一种应用于直升机防撞雷达的高口面效率W波段单脉冲双反射面卡塞格伦天线.口面分析方法的提出解决了W波段反射面天线口面相位分布不均匀的缺陷,从而有效地提高了口面的利用效率.利用该方法,本文研究并制作了口径为135 mm、焦距为40.5 mm的W波段卡赛格伦天线,并且设计了由四个E面多缝隙电桥和四个四分之一波导波长延迟线级联构成的和差网络.经测试,该单脉冲天线在93 GHz具有38.6 dBi的和波束增益,相应的口面效率为54.7%;差波束的零深优于-22 dB,副瓣电平小于-18 dB.测试结果与基于口面分析方法的仿真结果吻合,从而证明了本文所研究天线可以应用于高口面效率的W波段单脉冲系统中. 相似文献
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为了探测目标的极化特性,研制了工作在W波段的双极化单脉冲卡塞格伦天线.天线由主反射面、副反射面、馈源喇叭、正交模耦合器及和差器组成.天线主反射面口径为137 mm,馈源为五喇叭形式,正交模耦合器采用渐变波导匹配方案,和差器通过平面型定向耦合结构实现.通过将馈源喇叭、正交模耦合器及和差器集成设计,减小了连接损耗,压缩了天线纵向尺寸.测试结果表明,天线驻波带宽约3. 7 GHz,极化隔离度优于35 dB,和波束增益大于37. 9 dBi,副瓣电平优于-15 dB,差波束零深优于-25 dB.天线在W波段实现了较好地双极化单脉冲性能. 相似文献
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高效率低旁瓣天线口面场分布函数研究 总被引:1,自引:1,他引:0
在赋形双反射面天线中,口面场分布函数对天线电气性能起到至关重要的作用。口面场分布函数妆接影响天线的增益和近角旁瓣。在传统卫星通信地面站中,要求天线第一旁瓣电平在-14dB以下,口面利用率在90%左右,而射电天文望远镜要求天线第一旁瓣电平小于-20dB,口面利用率要求在85%以上。研究并给出了一种整个口面能量均匀分布而外边缘低锥销的口面场分布函数,可以满足高增益,低旁瓣的要求。 相似文献
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火控雷达中普遍使用一种双波段(Ⅰ、Ⅱ波段)跟踪天线——四喇叭单脉冲卡塞格伦天线,该天线具有较窄的和波束,搜索、发现目标困难。数值计算和实验测试表明,通过对Ⅰ波段副反射面进行赋形,可使Ⅰ波段的和波束成为扇形波束(用于搜索、发现目标),并且Ⅰ、Ⅱ波段天线都可用于目标跟踪。 相似文献
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为了实现一种具有高口面辐射效率、斜波束出射能力的口径天线,采用几何光学方法设计了一种偏馈双反射面天线.天线主反射面采用赋形设计,副反射面的设计过程中采用Snell定理作为约束条件.通过理论公式、数值模拟仿真和实验测试研究,实现了一种出射波束口径为110 cm、天线口面场分布为抛物形分布、波束出射方向与竖直方向成20°夹角的赋形偏馈双反射面天线.在中心频率95 GHz下,实测天线增益为59.7 dB,第一副瓣电平为-19dB,天线口径效率达到78%. 相似文献
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针对传统切换式多馈源的低剖面反射面天线结构复杂,不能多频段同时工作的问题,介绍了一款四波段单馈源低剖面环焦反射面天线及设计方法。该天线工作在四波段14~14.5 GHz, 11.45~12.75 GHz,19.6~21.2 GHz,29.4~31 GHz。整体天线采用双槽深波纹喇叭单馈源、通过口面场分布和多项式拟合过渡函数的方法构造的赋形副反射面和主反射面。用电磁仿真软件进行了建模仿真和验证。实测结果表明,整体天线较传统天线的效率提高12%以上,第一旁瓣<-14 dB,指标满足设计要求。 相似文献
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提出了一种新型共面双波段单脉冲天线设计方法, 分别给出了两个频段的驻波曲线和辐射方向图的测试结果.该天线在有限的空间内采用小型化边缘馈电的微带天线阵列与波导缝隙天线阵列复合, 实现了两个频段的单脉冲天线共口径排布, 天线厚度29 mm, 重量小于1 kg.测试结果表明该新型双波段单脉冲天线能够在X、K两个特定频段下分别得到-19 dB和-22 dB的副瓣性能及38%和45%的辐射效率, 实现了与单模相当的单脉冲方向图性能, 满足了未来复合制导系统对高性能天线的需求. 相似文献
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A multielement high power monopulse feed was investigated for excitation of a phased array. This feed has the advantages of high antenna efficiency, effective independent sidelobe control for the sum and difference patterns, and high power handling capability. A 32-element device has been designed which yields theoretical sidelobe levels less than -31 dB for both the sum and difference patterns over the 2800 to 3200 MHz frequency band. The aperture efficiency is 69.5 percent which includes 0.1 dB spillover loss and 1.40 dB tapering loss. The difference slope efficiency defined as the actual slope gain over the maximum possible value is 50 percent at midband. An experimental feed was constructed to verify the predicted performance characteristics. Measured data on both the radiation patterns and the antenna gain agreed very Well with the analytical results. The measured sidelobe level is below -30 dB for all sum and difference beams over the 2800 to 3200 MHz. In addition, this feed can be designed for low power intensity at the feed aperture so that very high power operation can be attained. 相似文献
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A unified formulation of the optimization of monopulse antenna performance indices for a specified sidelobe envelope function and/or specified nulls of the pattern is presented. The performance indices considered are beam efficiency, gain factor, and angular sensitivity factor of rectangular and circular apertures. The unconstrained optimization of beam efficiency result in an integral equation, the solutions of which are prolate spheroidal wave functions for rectangular aperture and hyperspheroidal wave functions for circular aperture. These functions reduce, respectively, to Legendre and Zernike polynomials in the case of gain factor and angular sensitivity factor. The double orthogonality properties of these eigenfunctions are used for constrained optimization. The results obtained by this technique for the near-in sidelobes constrained at a uniform level are shown to be in agreement with the earlier works. The method is applicable for other aperture surfaces such as elliptical, ellipsoidal, and spherical. 相似文献
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基于准光技术在亚毫米波频段设计分析了一种单脉冲天线。采用时域有限差分(FDTD) 方法结合斯特拉顿-朱兰成(Stratton-Chu)公式对该准光单脉冲天线的辐射性能进行了严格的仿真分析。为了进一步抑制辐射和波束方向图的副瓣电平,引入了修正的介质双曲透镜。仿真结果表明,该单脉冲介质透镜天线具有良好的辐射特性,其中和波束的副瓣电平小于-11.9 dB,差波束的零深低于-30.0 dB,不平衡度小于0.50 dB。 相似文献
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Corona P. Ferrara G. Gennarelli C. 《Antennas and Propagation, IEEE Transactions on》1989,37(8):990-995
Universal curves giving the main-lobe reduction and the first sidelobe level change versus the measurement distance are furnished for various aperture distributions. The widely used Rayleigh 2D 2/λ distance criterion (where λ is the radiated wavelength and D is the distance to the antenna) is shown to be unsatisfactory, since the minimum measurement distance depends both on the aperture distribution and on the specific far-field parameter under measurement. It is found that, in order to measure accurately the pattern of antennas with ultralow sidelobes, a measurement distance much greater than the Rayleigh one is needed. Such a distance is more than safe for measurement of the antenna gain and antenna patterns with moderate sidelobe level, but it is greater than necessary to measure the principal parameters of interest in a monopulse system. This latter conclusion is in full agreement with reported experimental results. Some experimental results concerning a monopulse antenna reported 相似文献
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This paper describes the design and performance of a conical Potter horn antenna which can generate sum or difference far field patterns suitable for monopulse tracking applications. The antenna consists of a horn antenna fed with a metal post loaded polarizer which is energised by suitably phased 50-/spl Omega/ matched coaxial probes. The prototype demonstrator designed here operates in the frequency range 8-8.6GHz with sum and difference patterns obtained by using a very simple phasing circuit. At 8.5GHz, the gain of the sum pattern is 18.6dB and the in the difference pattern is 26dB at boresight. 相似文献
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A new method for applying continuous aperture design results to discrete antenna arrays is described. Instead of sampling the continuous aperture distribution, one requires that the pattern zeroes found in the continuous case also occur in the starting pattern for the discrete case. If the resulting pattern does not meet the design goal, a perturbation procedure is applied to the discrete distribution in order to bring the final pattern within specification. The approach is illustrated by two examples: 1) a 20 dB Taylor pattern, modified so that the innermost three sidelobes on one side of the main beam are down 30 dB and 2) a pattern in which the innermost seven sidelobes on one side of the main beam are at -25 dB, whereas on the other side they cascade in 5 dB steps from -45 dB next to the main beam to -15 dB for the seventh sidelobe. 相似文献