共查询到18条相似文献,搜索用时 140 毫秒
1.
2.
3.
八木天线是一种常用的天线形式.本文将Minkowski分形环应用于八木天线设计中,利用分形结构的空间填充特性来减小天线的横向尺寸,从而实现天线小型化设计.设计了工作于880~960MHz的6元二阶Minkowski分形环八木天线,以矩量法为核心对设计天线进行数值分析,将线天线模拟为细带线模型,天线表面采用三角单元进行剖分,RwG基函数作为电流展开函数.同方环八木天线进行了比较,在驻波特性、辐射特性相似情况下,分形环八木天线的尺寸缩减了29.8%. 相似文献
4.
基于UV技术加速的矩量法/物理光学混合算法(UV/MoM-PO),研究了电大尺寸载体对位于其附近的阵列天线性能的影响.在UV/MoM-PO算法中,载体被设置为PO区域,阵列天线被设置为MoM区域.PO区域采用三角面片剖分,并用RWG基函数展开,MoM区域则用线段剖分,并用分段线性基函数展开.根据与MoM区域的远近,将PO区域的单元分组,其中每个小组与MoM区域的相互作用矩阵采用UV分解技术快速得到.给出了两个具体的算例,并与多层快速多极子(MLFMM)的结果进行了比较,表明本文的算法有较好的计算精度. 相似文献
5.
6.
7.
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
8.
利用矩量法对探针馈电的蘑菇型EBG微带天线的电磁辐射特性进行了分析。首先建立了天线模型,采用细导线的带模型将馈电探针和EBG短路过孔等效为细带,并与EBG金属表面和微带贴片一样均采用平面三角面元剖分,RWG基函数作为电流展开函数,将线面连接问题转化为面面连接问题。然后给出了采用空域矩量法对天线辐射特性进行分析的全过程,并介绍了激励源的添加模型。最后对蘑菇型EBG微带天线的回路损耗、输入阻抗和方向图等特性进行了分析计算,相关结果与FEKO和文献吻合良好,验证了本文方法的正确性。 相似文献
9.
三维散射与辐射问题通常采用电场积分方程(EFIE)结合矩量法(MoM)求解,而基函数是决定矩量法精度和效率的重要因素。本文针对采用三角形网格剖分会引起未知元过多而采用四边形网格剖分会因为网格质量变差而影响计算精度的问题,提出一种基于三角形与四边形混合网格的混合基函数,应用于散射体RCS和天线阻抗特性计算。结果表明,相比于三角形剖分,混合基函数能够在减少未知元个数的同时获得较高的精度;另外也解决了基于单纯四边形网格的基函数在网格质量较差的情况下不能准确模拟表面电荷的问题。 相似文献
10.
11.
12.
13.
Kennedy T. F. Fasenfest K. D. Long S. A. Williams J. T. 《Antennas and Propagation, IEEE Transactions on》2006,54(12):3608-3613
Increasing the number of antennas for wireless communications, while concealing them within their environment, is an area of great importance as demand for wireless devices increases. One method to achieve this goal is to use the existing conducting objects in an environment as antennas. This requires altering the natural current distribution on conducting objects such that optimal radiation properties can be obtained. In this paper, a composite dielectric bead element is introduced for this purpose on electrically large wire structures. The operation of the bead element is described using transmission line theory, and a wire model of the element is given. Using the wire model, the loading for several electrically large wire structures is designed such that they resonate and radiate similarly to a half-wavelength dipole 相似文献
14.
15.
选择RWG和Costa基函数用矩量法分析了线面结合的天线问题,计算了月球射电仪典型天线的输入阻抗和方向图.给出了单极和双极天线的典型结果,得到了金属盒大小对结果的影响关系.对于双极天线还对比了中馈和边馈两种方式的结果.在计算中,使用了9点高斯积分法处理奇异积分,得到了较好的效果. 相似文献
16.
I. P. Korshunov E. N. Korshunova A. N. Sivov A. D. Shatrov 《Journal of Communications Technology and Electronics》2007,52(4):365-378
Three types of elements with an anisotropically conducting surface—a strip, a cylinder, and a sphere—that are of interest for certain applications are considered. It is shown that these electrodynamic objects exhibit resonance properties even when their dimensions are small compared to the wavelength and that resonances occur in both 2D and 3D diffraction problems. It is found that the presence of low-frequency resonances provides for a wide variety of electrodynamic properties of the objects under study and of gratings formed from such elements. Examples of implemented waveguides, waveguide mode converters, frequency-selective circular-polarization antennas, and polarization transducers are presented. 相似文献
17.
18.
Simple and Accurate Analytical Model of Planar Grids and High-Impedance Surfaces Comprising Metal Strips or Patches 总被引:1,自引:0,他引:1
Luukkonen O. Simovski C. Granet G. Goussetis G. Lioubtchenko D. Raisanen A.V. Tretyakov S.A. 《Antennas and Propagation, IEEE Transactions on》2008,56(6):1624-1632
Simple analytical formulas are introduced for the grid impedance of electrically dense arrays of square patches and for the surface impedance of high-impedance surfaces based on the dense arrays of metal strips or square patches over ground planes. Emphasis is on the oblique-incidence excitation. The approach is based on the known analytical models for strip grids combined with the approximate Babinet principle for planar grids located at a dielectric interface. Analytical expressions for the surface impedance and reflection coefficient resulting from our analysis are thoroughly verified by full-wave simulations and compared with available data in open literature for particular cases. The results can be used in the design of various antennas and microwave or millimeter wave devices which use artificial impedance surfaces and artificial magnetic conductors (reflect-array antennas, tunable phase shifters, etc.), as well as for the derivation of accurate higher-order impedance boundary conditions for artificial (high-) impedance surfaces. As an example, the propagation properties of surface waves along the high-impedance surfaces are studied. 相似文献