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将轴槽和直槽相结合,设计了一种工作于Ka波段的新型双槽波纹喇叭天线,模变换段采用轴槽设计,辐射段采用直槽设计,通过仿真试验,获得了波纹喇叭天线轴槽和直槽的最佳数目,并在此基础上,优化了槽宽、槽深及光滑圆波导的长度,得到了辐射性能最佳的天线结构。将所设计的双槽波纹喇叭与传统的单槽波纹喇叭作为馈源,分别应用到卡塞格伦天线中进行了仿真试验。仿真结果表明,所设计的双槽波纹喇叭具有性能更优的辐射特性和驻波特性,作为馈源使用时,卡塞格伦天线在主极化方向上性能良好。 相似文献
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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。 相似文献
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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。 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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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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Realization of high-efficiency rectangular horns is investigated by means of mode generation and profile optimization. Conditions required for maximum efficiency of an aperture array are derived and made specific to a rectangular aperture with twofold symmetry. It is shown that aperture coupling has a significant effect on aperture efficiency through mode coupling. Efficiencies in excess of 100% are predicted for aperture sizes that are slightly greater than an odd multiple of half-wavelengths. The method described here results in more compact horns than obtained by using conventional linear tapers or steps. Results are presented for horns suitable for array feeds or directly radiating array applications that achieve aperture efficiencies close to 100% with horns of aperture size ranging from 1.25 to 3 wavelengths and at the same time have a return loss 20 > dB and cross-polar isolation > 22 dB. Measured results are given for an experimental compact horn that has high efficiency over an 8% bandwidth. The agreement between computation and measurement is within the limits of experimental error and this is obtained without any special surface treatment on the inside surfaces. 相似文献
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Burkhard Plaum 《Journal of Infrared, Millimeter and Terahertz Waves》2018,39(10):984-995
This paper presents the optimization and characterization of broadband circular horn antennas with smooth walls. These antennas are simpler and easier to manufacture than corrugated horns. They work by converting the incoming fundamental mode to a mode mixture, whose total field corresponds to a Gaussian beam pattern at the aperture. The geometry of the horn is found by an optimization algorithm. While smooth-wall horn antennas have been designed for many years, they are inherently band limited because they rely on a correct multimode interference in the aperture to match the total field to a Gaussian distribution. The presented method achieves significantly larger bandwidths by allowing the Gaussian beam parameters, and thus the required mode spectrum in the aperture, to vary with the frequency. Together with an appropriate mirror optics, a receiver system with a bandwidth of more than 3 octaves could be realized. 相似文献
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Liu K. Balanis C.A. Birtcher C.R. Barber G.C. 《Antennas and Propagation, IEEE Transactions on》1993,41(10):1379-1389
A hybrid numerical technique is developed for electrically large pyramidal horn antennas radiating in free space. A stepped-waveguide method is used to analyze the interior surfaces of the horn transition. The electric field integral equation (EFIE) is employed on the outer surfaces of the pyramidal horn including the radiating aperture. Meanwhile, the magnetic field integral equation (MFIE) is used on the aperture to relate the aperture fields and those in the horn transition The resultant hybrid field integral equation (HFIE) is solved numerically by the method of moments. This formulation is both accurate and numerically stable so that high-gain microwave pyramidal horns can be analyzed rigorously. Far-field radiation patterns, both computed and measured, are presented for three electrically-large X-band horn antennas. The comparisons demonstrate that this method is accurate enough to predict the fine pattern structure at wide angles and in the back region. Computed far-field patterns and aperture field distributions of two smaller X-band horns are also presented along with a discussion on the validity of the approximate aperture field distributions routinely used in the analysis and design of pyramidal horns 相似文献
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A step horn structure is presented that yields about 90% aperture efficiency with low cross-polar radiation. It is found that for obtaining high aperture efficiency, the horn aperture should consist of only the TE/sub z/ type of modes in appropriate amplitudes and phases. The desired TE/sub z/ modes are produced using multiple steps in the horn walls. The distances between the steps are critical to suppress the undesired TM/sub z/ modes. Radiation characteristics of high efficiency circular and square horns are presented and potential applications of such high efficiency horns are discussed. 相似文献
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M. T. Chen C. -Y. E. Tong S. Paine R. Blundell 《Journal of Infrared, Millimeter and Terahertz Waves》1997,18(9):1697-1711
We present measurements of the near-field beam profiles of two corrugated feed horns with center frequencies of 216 and 300 GHz. Both co-polar and cross-polar components of the electric field have been probed across the operation band of the horns. A full-wave numerical near-field transformation, based on a vector Kirchhoff integral, is implemented to transform the measured field to the horn aperture for a comparison with the ideal aperture field. From the overlap integral of the transformed and the ideal field, we conclude that the field radiated by these horns is the HE11 mode, to a purity of better than 99%. 相似文献
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The radiation characteristics of diagonal horns are investigated by means of Gaussian-Hermite modes. It is shown that, for reasonably long horns, the beamwidths in the principal and 45° planes are equal to within 10%, and all sidelobes are below -15 dB. It is also demonstrated that the phase center of a diffraction-limited horn is close to the aperture, whereas the phase center of a constant-beamwidth horn is behind the throat. The maximum coupling to the lowest order copolar Gaussian mode is 84%, and the total amount of power coupled into the cross-polarized lobes is 9.5%. More significantly, the aperture efficiency of a Cassegrain antenna fed by a diagonal horn has a maximum value of 81%, which compares with 87% for a corrugated horn. The maximum efficiency is achieved when the aperture of a diffraction-limited horn is placed at a confocal tertiary focus, although a secondary focus gives an aperture efficiency that is only 10% lower, suggesting that diagonal horns are suitable for focal-plane arrays 相似文献
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It is shown how the radiation patterns of conical horns can be understood in terms of Laguerre-Gaussian beam modes. This approach provides a simple method for calculating the horn radiation pattern as it propagates through a multielement optical system consisting of lenses or offset mirrors with large focal ratio and/or a small angle of incidence, and can be used in quantitatively determining aperture efficiencies for systems where conical horns are coupled to antennas via tertiary optics. The resulting aperture efficiency results and a practical quasioptical system fed by a conical horn are discussed 相似文献
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A hybrid technique is proposed to solve the entire problem of corrugated and noncorrugated rectangular horns without the usual approximations. The horn antenna is simulated by a multistepped waveguide structure radiating into half-space. The procedure is composed of three steps. First, assuming the horn to be terminated by infinite metallic flange, the aperture problem is accurately solved by a hybrid modal-spectral method (HMSM). Second, the modal analysis (MA) method and scattering matrix concept of waveguide discontinuities are employed to solve the transverse multidiscontinuity problems. Finally, the two methods are combined (MA-HMSM) to solve the entire problem of the horn antenna. The proposed technique allows to obtain not only the radiation patterns, but also the reflection and near-field characteristics of the horn, without any restriction on the geometry (semiflare angles, profiled horn contours, corrugations). A good agreement between theoretical predictions and experimental results has been obtained for several horns. 相似文献
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The effect of higher order interactions in the coupling between twoH -plane sectoral electromagnetic horns on the field distribution at the aperture of the transmitting horn is calculated using the point matching technique. A nonsingular integral equation for the induced current in the receiving horn, due to the initially incident wave from the transmitting horn, is formulated using a conformal transformation which maps the cross sectional contour of the receiving horn onto two circles on which the induced currents are finite. The solution leads to a modified field distribution in the transmitting aperture which is then employed in Hu's near-zone power transmission formula to compute a gain correction factor forH -plane sectoral horns. It is shown that the correction factor oscillates about that reported by Chu and Semplak with an amplitude which increases for smaller separation distances. 相似文献
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Mutual coupling between sectoral horns side by side 总被引:1,自引:0,他引:1
The mutual coupling between two sectoral horns side by side is formulated in terms of the rays, modes, and mode caustics excited in each horn. The coupling term is attributed to the multiple interaction between the aperture edges of both horns and is calculated using Keller's geometrical theory of diffraction. It is shown that this asymptotic method leads to an excellent agreement with experiment and is a considerable improvement over more complicated solutions based on the Huygens' principle. 相似文献