共查询到18条相似文献,搜索用时 343 毫秒
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基于有向阵元的圆形阵列方向图综合 总被引:4,自引:0,他引:4
由于圆形阵列方向图所具有的特性,使得圆阵正得到日益广泛应用,但是圆阵方向图却具有相对主瓣 较高的副瓣电平.为此,本文通过引入有向阵元并适当选取其辐射函数有效地解决此类问题.仿真结果表明:有向阵元 对圆阵方向图及自适应零点形成有明显改善作用,但对线阵基本上无作用. 相似文献
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本文提出了M个正交振子元相控圆阵天线的理论。它包括:阵远区辐射场型推导;径切正交振子元场型方向可控加权因子的导出,在此课题方面打破了有向元相控圆阵没有对称轴的传统观念,在这个基础上提出了正交振子元圆阵双重定向性质及空间辐射基本规律的分析;根据同相定向性质,提出形成多波束中心相控网络的理论结构。 这一理论,对短波、超短波、微波方面用一付圆阵天线在360方位范围内实现同时多方位接收,在工程上有着直接的指导意义,并对连续扫描大型圆阵及二维阵的分析也有一定参考价值。 相似文献
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由于多波束天线系统在近代通信中占有愈来愈重要的地位,本文从阵辐射空间基本性质出发,将最小均方自适应技术扩展应用于多波束天线系统,从而提出自适应多波束三维阵天线课题。它包括:自适应三维阵系统辐射图型表达式;瞬态阵辐射图型生成过程;阵系统输出信/噪比表达式;自适应多波束网络的构成。 相似文献
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本文对M个正交振子元相控圆阵天线方向增益指标最佳化进行了研究。通过径切正交振子元加权因子辐射场型方向可控性质,把只适用于同样排列方向的相同有向元组成的阵用埃米特型比的形式表示方向增益最佳化理论扩展到M个正交振于元相控圆阵天线课题。 本文包括:阵远区辐射场公式;径切正交振子元加权场型方向可控因子的导出;调整激励(含幅度与相位在内)以及仅调整相位激励方向增益指标最佳化公式的推求。 相似文献
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在接收阵天线中,提高信/噪比,即最大化增益并有效地抑制干扰一直成为研究的中心课题。本文围绕着这个中心,提出了振子型合成元三维相控阵天线辐射空间多重控制理论。它包括:合成元三维阵远区辐射场表达式;合成元在三维空间辐射场型最大方向可控性质;阵辐射场图型多重零点控制的基本关系;在多重零点控制强制条件下,合成元三维相控阵天线方向增益最大化。 相似文献
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本文导出了正交环元辐射场型方向可控加权因子。它表明:在加权条件下,不同取向正交环相控圆阵,可应用方向图相乘原理,把只适用于同样取向的相同有向元组成的阵,用Hermitian型比表示的方向增益最佳化理论,扩展到N个不同取向的正交环相控圆阵天线。 相似文献
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A numerical pattern synthesis algorithm for arrays 总被引:17,自引:0,他引:17
A numerical technique for pattern synthesis in arrays is presented. For a given set of elements, the technique allows one to find a set of array coefficients that steer the main beam in a given direction and yield sidelobes meeting a specified criterion, if such a set of array coefficients exists. If the pattern specifications cannot be met with the given elements, the algorithm finds the best attainable pattern. The advantage of this technique is that it can be used with an arbitrary set of array elements. Different elements in the array can have different element patterns, and the array can have arbitrary nonuniform spacing between elements. The synthesis technique is based on adaptive array theory. The given array elements are assumed to be used as the elements of an adaptive array. The main beam is pointed in the proper direction by choosing the steering vector for that direction, and the sidelobes are controlled by introducing a large number of interfering signals at many angles throughout the sidelobe region. The algorithm iterates on the interference powers until a suitable pattern is obtained 相似文献
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Liu Zhenwei 《电子科学学刊(英文版)》1984,1(2):65-74
The multi-beam antenna systems have become increasingly important in modern communications. In this paper, the author proposes
according to the properties of array radiation space the use of the LMS’ adaptive techniques in multi-beam antenna systems.
This proposal includes the radiation pattern of three-dimensional adaptive arrays, the evolution of the radiation pattern
of adaptive arrays, the signal-to-interference plus noise ratio of the array system output, and the structure of the adaptive
multi-beam networks. These will be discussed in the order mentioned. 相似文献
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In antenna arrays, the number of nulls that can be formed independently is equal to or less than the number of array elements minus one. Therefore, if the number of interferences exceeds the number of freedom for pattern synthesis in adaptive arrays, nulls in the radiation pattern can not be steered toward each interference direction. To clarify the behavior of the adaptive array in such an environment, an analysis is made for the case where two interferences are impinging on the two-element directionally constrained adaptive array. As a result, it is proved that the adaptive array acts to reduce the undesired noise power at the array output. However, improvement in output signal-to-noise ratio is insufficient because of the limitation in null formation. 相似文献
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A conformal array is presented that provides, by means of single-pole multithrow switches and microstrip power dividers, either an omnidirectional or an electronically despun directional radiation pattern. Switching techniques for scanning the directional pattern of circular arrays are discussed. The design parameters and measured results of an experimental 64-element array flush-mounted on a cylindrical spacecraft, are presented. Over the 40-percent bandwidth atS band, measured results show close agreement with theory. 相似文献
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任意形状旁瓣波束形成技术研究 总被引:2,自引:0,他引:2
在自适应零陷形成的基础上,提出了一种自适应加权算法,用于任意阵型阵列构成具有任意形状旁瓣的波束图,并考虑基元方向性对波束图的影响.给出了实现自适应加权算法的三个步骤,预先设定所需旁瓣形状及旁瓣级,采用循环,最终使旁瓣与预设形状吻合.将该算法用于均匀线阵和抛物线阵,均得到期望的结果,并与道夫-切比雪夫加权作了相应比较.研究表明,基元的方向性对该算法波束形成的影响很小,新算法可以消除基元宽带方向性对波束的影响. 相似文献
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In the presence of two directional interferences, the radiation pattern of an adaptive array can be expressed in terms of the powers of the sources and their directions of arrival. This is used to illustrate the performance and operation of adaptive arrays in the case of multiple jammers. In particular, the case of main-beam jamming is examined. 相似文献
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天线阵列方向图的一种数值综合算法 总被引:4,自引:0,他引:4
本文提出了一种新型阵列综合算法,目标方向图迭代算法。这种算法与现有的阵列综合方法不同,它通过对目标方向图的迭代来调整实际方向图的形状,是一种纯数值的阵列综合算法。这种算法适用于任意结构阵列的方向图综合,计算效率高,可以满足实际工程的需要。作为验证,本文综合了一些具有代表性的天线阵列,给出了计算结果,并对结果进行了讨论。 相似文献