共查询到19条相似文献,搜索用时 156 毫秒
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本文阐明了在使用口径天线在远场区的冲激响应的概念时,远场区是对激励天线的实际信号而言,并非对为求冲激响应而施加在天线上的δ函数而言;远场区的冲激响应在距离上的适用范围决定于激励信号的频率范围。 相似文献
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在近场测量系统中,天线口径诊断是其中一项重要功能,它能够帮助天线设计师发现相控阵天线设计或者网络配置问题.平面近场中的口径诊断技术已经广泛地应用在雷达天线测试中,在球面近场测量中同样需要这种算法.本文基于球面坐标系下电磁场模式方法,得到球面近场条件下的口径反演算法.在仿真模型中计算得到了被测天线的口径场分布,计算结果与理论模型结果吻合.对X波段阵列天线进行了实际测试,得到了不同配置下的阵列天线口径反演结果,经过数据比对,证明了本文算法的幅度反演精度优于1 dB. 相似文献
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正 (一)引言 在各种军用和民用雷达中,广泛使用各种型式的端馈阵列天线。这种天线在脉冲信号激励时产生的瞬变过程会影响雷达系统的角分辨力、测角精度、杂乱回波电平、探测距离和距离分辨力。由于分析天线瞬变过程的有效工具是天线的冲激响应,因而它在雷达检测理论中是一个重要的特性函数。 但是,端馈阵列天线的冲激响应问题在现有文献中尚未得到系统的研究。文献[1]对 相似文献
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本文讨论了天线口径衍射场分布的相似性问题。对一定的口径分布,当口径特征尺寸、波长及观察平面至口面的距离改变时,衍射场分布存在两种不同的相似性。即电尺寸恒定性的“严格相似性”及电尺寸变化时的“近相似性”。 相似文献
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Hu Hannan 《电子科学学刊(英文版)》1986,3(3):211-219
On the basis of the equation of the Fresnel-Kirchhoff scalar diffraction field, it is shown that the impulse responses of
parallel-fed aperture antennas of arbitrary configuration with arbitrary aperture amplitude distributions and those of end-fed
rectangular aperture antennas with arbitrary aperture amplitude distributions can all be expressed by the aperture amplitude
distributions, and that the impulse responses of rectangular aperture antennas with separable aperture distributions and those
of circular aperture antennas with circularly symmetric distributions are special cases of the above general ones. 相似文献
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Hu Hannan 《电子科学学刊(英文版)》1985,2(3):201-210
On the basis of the equation of the Fresnel-Kirchhoff scalar diffraction field, the impulse responses of parallel-fed and
series-fed rectangular antennas with separable aperture distributions and the impulse responses of parallel-fed and center-series-fed
circular antennas with circularly symmetric distributions are derived—all of them can be expressed in the aperture amplitude
distributions. 相似文献
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A phase-only method for the synthesis of planar aperture antennas for a given complex radiation pattern in one plane is reported. The problem is reduced to determining an appropriate aperture phase distribution in the form of a ruled function and solved for apertures with rectangular shape and an arbitrary amplitude distribution and for apertures of arbitrary shape and amplitude distribution. This method can be used for controlling the pattern of phased-array antennas. Results of computer modeling are presented 相似文献
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A theoretical and experimental study is made of the effects of a dielectric of arbitrary thickness, permittivity, and loss tangent upon the aperture field distributions and the far-field radiation pattern characteristics of long-slot leaky-wave antennas cut on the broadwall of a rectangular waveguide and mounted in an infinite ground plane. The relevant integral equations for determining the aperture fields are developed and then solved using the moment method. Expressions for the far-field radiation patterns and isolation responses are developed. Calculated and experimental results for several antennas are presented and discussed 相似文献
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Meandering long slot leaky-wave waveguide-antennas 总被引:1,自引:0,他引:1
A theoretical study is made of the aperture field distributions, the far-field amplitude patterns, and the mutual coupling characteristics of several long leaky-wave slot antennas cut on the broadwall of a rectangular waveguide mounted in an infinite ground plane. Straight long slots have high inner sidelobes in the far-field amplitude patterns, which reduces their utility as high-performance antennas. To reduce these sidelobes, a long slot may be meandered from waveguide centerline to sidewall and back to centerline in such a way to produce the desired radiation patterns. Calculated results for antennas of several meander patterns are presented and discussed 相似文献
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Gaussian field expansions for large aperture antennas 总被引:1,自引:0,他引:1
An approximate theory of large aperture antennas is developed where aperture, Fresnel, and far fields are expressed in the form of Ganssian field expansions. First, aperture fields, i.e., aperture distributions, are expanded in orthogonal Hermite-Ganssian and Laguerre-Gaussian functions for antennas with rectangular and circular geometries, respectively. Then solution of the Fresnel-Kirchoff diffraction integrals yields the Fresnel and far field expansions. Care is taken to assure the direct transformability of the aperture fields. Optimal scale factors contained in the aperture field expansions are derived and lead to structured field distributions where sidelobes are added sequentially as more terms in the expansions are used in the computations. Tables of optimal scale factors and series coefficients are provided for cosine, truncated Ganssian and Taylor aperture distributions. Several examples are provided that demonstrate the usefulness of the formulas. 相似文献
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An analysis is carried out to determine the discontinuity susceptance of a circular or rectangular aperture in the transverse plane of a circular waveguide. Closed-form solutions based on the scattered amplitude calculations and aperture coupling theory are derived. Example solutions for a small circular aperture and a resonant rectangular aperture are given. The calculated results agree very well with the experiments. The results have many applications in the design of circular waveguide components and circular waveguide-backed aperture antennas 相似文献
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An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with arbitrary complex aperture. Also, the gain drop and sidelobe degradation due to random amplitude and phase errors and element (or T/R module) failures are investigated. 相似文献