共查询到16条相似文献,搜索用时 171 毫秒
1.
1/R居中Cantor集合分层介质是一种分形结构。这种结构在某些光学器件上已获得应用。如果将它引入微波领域,可望构造出一类新型的微波器件。本文主要研究了在以这种分形介质填充的波导中波的反射传输特性。利用网络的自相似性,导出了反射系数、传输系数的简单递推公式。最后,给出具体分析实例,并讨论了计算结果。 相似文献
2.
3.
4.
本文按分形几何的自相似原理构造出一种具有自相似分布结构的随机粒子模型,求得了其数密度相关函数孔子。这种模型有确定的构造方法,在结构上具有自相似性,并可按其结构特征求得其相关函数,因而便于应用于随机介质与波的相互作用的研究和计算机模拟。本文应用此模型分析了雷达回波功率与距离的关系。结果与Rastogi等人(1990)的数值模拟结果完全一致。 相似文献
5.
6.
30CrMnSi断口表面的分形特征周善民王伟兰胡小波(南昌航空工业学院,南昌330034)断口表面是粗糙的和不规则的,具有近似的自相似性质,可以看成是一种分形结构,分形维数D是断裂表面分形结构时粗糙度的一种度量。选用30CrMnSi合金钢为研究对象,... 相似文献
7.
8.
9.
该文采用全波 FDTD分析方法对Hilbert分形天线进行分析。输入阻抗的计算结果验证了分形天线结构自相似性导致电特性的频率周期性变化这一规律。所得结果与有关实验数据吻合较好。研究结果还表明Hilbert分形天线具有缩小天线结构尺寸的优点,相对于一般振子天线来说结构尺寸大大缩小,文中分形天线长度缩小为相应偶极天线的1/7。对Hilbert分形天线而言其维数越高,天线尺寸缩小越大,但相邻分形阶数缩小幅度越来越小,同时对其方向图的全波分析说明Hilbert分形天线同振子天线的性能基本相似,方向图在谐振频段内基本保持不变。 相似文献
10.
基于最优扫描结构的分形IP核设计 总被引:1,自引:1,他引:0
描述平板显示系统中最优扫描结构所对应的自相似分形拓扑结构图,提出分形扫描核心模块架构,分析n位分形扫描的递推结构,研究扫描过程中的子空间码与位码序列的关键特征,推导出序列生成的通用逻辑算法。在此基础上,设计了适合各种灰度等级的参数化的分形IP核并得到仿真结果,同时给出了分形IP核的系统应用,证明所设计的IP核可以有效提高灰度扫描的利用率和FPD画面质量。 相似文献
11.
12.
An efficient recursive procedure for evaluating the impedance matrix of linear and planar fractal arrays 总被引:1,自引:0,他引:1
Werner D.H. Baldacci D. Werner P.L. 《Antennas and Propagation, IEEE Transactions on》2004,52(2):380-387
The self-similar geometrical properties of fractal arrays are exploited in this paper to develop fast recursive algorithms for efficient evaluation of the associated impedance matrices as well as driving point impedances. The methodology is demonstrated by considering two types of uniformly excited fractal arrays consisting of side-by-side half-wave dipole antenna elements. These examples include a triadic Cantor linear fractal array and a Sierpinski carpet planar fractal array. This class of self-similar antenna arrays become significantly large at higher order stages of growth and utilization of fractal analysis allows the impedance matrix, and hence the driving point impedances, to be obtained much more efficiently than would be possible using conventional analysis techniques. 相似文献
13.
Radiation characteristics of thin-wire ternary fractal trees 总被引:1,自引:0,他引:1
The multiband electromagnetic behaviour of thin-wire structures based on a ternary tree fractal geometry are investigated. As an example, experimental and numerical results are presented for the particular case of a three-band monopole structure, which show the expected self-similar behaviour at those bands. Some interesting properties are observed for these ternary tree fractal structures that are not evident in their Sierpinski monopole counterparts 相似文献
14.
Julien Chauveau David Rousseau François Chapeau-Blondeau 《Multidimensional Systems and Signal Processing》2010,21(2):197-211
To contribute to the important task of characterizing the complex multidimensional structure of natural images, a fractal
characterization is proposed for the colorimetric organization of natural color images. This is realized from their three-dimensional
RGB color histogram, by applying a box-counting procedure to assess the dimensionality of its support. Regular scaling emerges,
almost linear over the whole range of accessible scales, and with non-integer slope in log-log allowing the definition of
a capacity dimension for the histogram. This manifests a fractal colorimetric organization with a self-similar structure of
the color palette typically composing natural images. Such a fractal characterization complements other previously known fractal
properties of natural images, some reported recently in their colorimetric organization, and others reported more classically
in their spatial organization. Such fractal multiscale features uncovered in natural images provide helpful clues relevant
to image modeling, processing and visual perception. 相似文献
15.
从理论上推导了SC分形图像的衍射强度表达式,并用光学方法进行了SC分形互补屏的傅里叶变换,在频谱面上除中心处,分形互补屏给出了相同的衍射图样,而且也具有对称性和自相似嵌套结构。实验结果与理论上推导出的表达式相吻合。同时,验证了巴俾涅原理。 相似文献
16.
《Electronics letters》1999,35(17):1393-1394
The surface current distribution of a Sierpinski fractal antenna shows a self-similar behaviour determined by the self-similar properties of its geometry. The application of infra-red thermography to electromagnetic near field detection allows the experimental verification of the active region scaling of a fractal antenna operating at different bands 相似文献