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针对有限大平台部署多种传感器导致的严重的自干扰问题,提出了一种应用遗传算法实现的阵列天线共址干扰抑制技术。首先针对同平台上的阵列天线和其他天线建立了辐射和接收模型,然后将辐射特性和接收机抗干扰特性分别抽象为最优化问题的目标函数和约束条件,最后通过遗传算法进行最优化求解。该技术在不同辐射角度时能抑制共址干扰,具有一定的工程实用价值。 相似文献
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本文给出了一种分析微带印刷天线辐射与散射的数值方法。此方法将印刷天线按三角网格剖分,在导体表面建立积分方程,用全波离散镜像理论给出微带结构的空域格林函数的闭合表达式,未知电流用三角网格上的矢量电流基函数展开并用矩量法求解。与以往的矩形网格上基函数展开相比,此方法能更有效地逼近任意形状的微带结构,最后给出了几个数值结果 相似文献
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本文给出了一种分析微带印刷天线辐射与散射的数值方法。此方法将印刷天线按三角网格部分,在导体表面建立积分方程,用全波离散镜像理论给出微带结构的空域格林函数的闭合表达式,未知电流用三角网格上的矢量电流基函数展开并用矩量法求解。与以往的矩形网格上基函数展开相比,此方法能更有效地逼近任意形状的微带结构,最后给出了几个数值结果。 相似文献
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针对5G大范围覆盖的应用场景进行了设计探讨,提出通过对基站天线垂直面进行余割平方成形、以保证大范围覆盖应用场景下信号的均匀性的方法。首先通过算法推导,证明余割平方成形的功率辐射波束可满足5G信号均匀覆盖的要求;其次,采用约束最优化方法,把天线的方向性系数作为目标函数,把指定区域的波束电平作为约束函数,求解基站天线辐射单元的权值,得到满足余割平方成形的辐射方向图。在MATLAB环境下开发了实现此算法的程序。本文的创新之处在于用实际的单元方向图和约束最优化方法,在保证天线增益最优的前提下,综合出需要线阵列天线方向图。引入仰角单元与其他正常单元一起综合方向图,解决顶盲问题,是这个方法的一个应用实例。最后,仿真验证该方法,并设置场景对应用余割平方成形的天线与常规天线的信号覆盖进行比较,证明该方法对信号均匀性有极大的改善。 相似文献
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基于几何绕射理论,计算了位于导体圆柱上的单极子天线和惠更斯元面天线的辐射方向图;利用该方向图,分析比较了不同天线之间的隔离随天线指向的变化情况。结果表明:选择适合的天线类型及适合的安装角度能够改善天线间隔离度;几何绕射理论是解决导电圆柱体上天线的辐射问题的一种有效方法;应用远区辐射场的方向函数估算耦合系数是一种简单可行的方法。 相似文献
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辫接导线引起的电磁泄漏,是屏蔽视频电缆泄漏最严重的部分。利用广义二端口网络法和天线理论求解视频电缆的辐射;从理论上分析了产生这种结果的原因,并提出减少这种辐射的方法,该方法对辫接效应的抑制大于20dB. 相似文献
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Extensive analysis of wire antennas using method of moments (MoM) has been performed over the past decades. Despite the thorough understanding and widespread use of the wire antennas, higher order modeling of wire structures has received little to no attention over the years. This may be because the inaccuracies associated with the classic reduced kernel approach used to analyze wire antennas have precluded the use of higher order basis functions. This paper combines a new method for computing integrating the cylindrical wire kernel with higher order basis functions for the accurate modeling of wire antennas. Numerical results demonstrate the higher order convergence of the approach 相似文献
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Tie Jun Cui Weng Cho Chew 《Antennas and Propagation, IEEE Transactions on》2002,50(3):301-307
Based on the accurate model developed in our previous paper, a general method is proposed to analyze wire structures in the free space or above multilayered media, which is valid from very-low to microwave frequencies. In this method, loop-tree basis functions have been applied to overcome the low-frequency breakdown problem, which can represent the nature of the Helmholtz decomposition of the current. The proposed method can be used to study wire antennas, or it can be incorporated with other methods to analyze circuit problems containing wire structures 相似文献
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利用矩量法对宽带圆形阵列天线的互耦特性进行分析。为了对较粗线天线进行精确分析,矩量法采用正弦差值基函数与点配法,并采用全域线天线积分核计算Pocklington方程,得到天线的广义散射矩阵,实现互耦分析。为了验证其计算结果,对所设计阵列天线进行了CST软件仿真和实验测试。仿真和测试结果表明:矩量法计算与CST仿真结果基本相同,实验测试结果在主波束方向、主波瓣宽度、副瓣电平等特性上与计算和仿真结果近似一致,说明此方法能够有效的对宽带阵列天线进行互耦分析。 相似文献
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Two numerical techniques for solving the current distribution on wire antennas, namely point matching and reaction matching, have been combined in a particular fashion to yield a new technique termed the "hybrid method." The hybrid method is well suited for a wire antenna mounted in a cavity. Over the antenna, piecewise sinusoidal basis functions with reaction matching are used, and on the support structure, point matching is used with pulse basis functions. The hybrid method has been applied to calculate the input impedance and the radiation efficiency of the three-turn loop antenna in an open circular cavity. Calculated input resistance of the antenna is found to agree quite well with measured data. Effects of varying the extent of recession of the antenna and varying the radius and the material of the antenna wire on the bandwidth, the efficiency, the antiresonance frequencies, and the general input reactance level of the antenna have been examined for a specific antenna geometry. The results are considered to be indicative of the general characteristics of a multiturn loop antenna with nearby support structure. The computer program that has been developed may be applied to a systematic parametric study of this type of antenna in order to optimize it for a particular application. 相似文献
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Chao-Ton Su Tai-Lin Chiang 《Electronics Packaging Manufacturing, IEEE Transactions on》2002,25(1):13-18
This study presents an integrated method in which neural networks, genetic algorithms, and exponential desirability functions are used to optimize the ball grid array (BGA) wire bonding process. As widely anticipated, the BGA package will become the fastest-growing semiconductor package and push integrated circuit (IC) packaging to higher level of compactness and density. However, wire bonding in BGA is difficult owing to its high input/output (I/O) count, fine pitch wire bonds, and long wire lengths. This study addresses two fundamental issues in the semiconductor assembly facility on its quest toward a defect-free manufacturing environment. First, the problem of exploring the nonlinear multivariate relationship between parameters and responses and second, obtaining the optimum operation parameters with respect to each response in which the process should operate. The implementation for the proposed method was carried out in an IC assembly factory in Taiwan; results in this study demonstrate the practicability of the proposed approach 相似文献
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Kinnaird C.D. Khotanzad A. 《Electronics Packaging Manufacturing, IEEE Transactions on》1999,22(3):233-243
One step in the assembly of integrated circuits is wire bonding, requiring expert knowledge to optimize critical process characteristics. This paper describes a fuzzy logic controller which sets parameters for the wire bonding process for gold ball wire bonds, specifically controlling bonded ball diameter and shear strength density. While the focus is on control of ball bonds, the method is general and may be applied to other bonding methods with minor modifications. The design of the fuzzy engine and the development of rules based on both operator experience and textual sources are discussed. An adaptation technique is developed to tune the controller's membership functions based on the measured results of the process. The controller has been tested on actual devices in an industrial setting; results show improved process control in terms of consistency and reduced operator adjustment 相似文献
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Imbriale W.A. Galindo-Israel V. Rahmat-Samii Y. 《Antennas and Propagation, IEEE Transactions on》1991,39(9):1352-1365
Poorer than expected surface reflectivity was observed in an early Tracking and Data Relay Satellite System antenna utilizing a tricot mesh weave. This poor reflectivity was determined to be caused by inadequate electrical contact at wire crossover points. A proper mathematical and numerical approach to assess the impact of wire junctions on reflectivity performance is developed. A mathematical method is presented for computing the surface reflectivity of complex mesh configurations like those on unfurlable-type spacecraft antennas. The method is based on the Floquet mode expansion to establish an integral equation for mesh wire currents. The equation is solved using the method of moments with triangular basis functions. It is observed that it is necessary to give special attention to the junction treatment among different branches of the mesh configurations. A vector junction current approach that resulted in satisfactory solutions for the current is described. The results of numerical simulations are compared against measured data and excellent agreement is observed 相似文献
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Nakano H. Kerner S.R. Alexopoulos N.G. 《Antennas and Propagation, IEEE Transactions on》1988,36(12):1667-1674
A printed wire antenna of arbitrary configuration is analyzed. The electric field tangential to the wire is derived using the current expanded by piecewise sinusoidal functions. These functions are also used to form the impedance matrix elements. Use of the stationary phase method leads to a simple expression for the radiation field. Numerical analyses based on the present formulation yield radiation characteristics of a zigzag dipole antenna, a loop antenna, and a round spiral antenna 相似文献