共查询到20条相似文献，搜索用时 749 毫秒
1.
2.
电磁波与等离子体之间的相互作用是等离子体物理学和高功率微波器件研究的重点,加载等离子体可以大幅度提高微波器件的输出功率和效率．文章提出了一种加载周期磁化变化等离子体圆波导的周期慢波结构,即加载轴向周期磁化正弦变化等离子体圆波导的介质周期结构,并研究了电磁波在该介质结构中的传播特性,根据严格的理论推导得出电磁波在其中传播的色散方程,并进行了数值计算和分析． 相似文献
3.
4.
5.
电磁波在负折射率介质中传播时,材料的介电常数和磁导率均为负数,从而表现出一些奇特的特性。为详细了解电磁波在正负折射率介质分界面的反常折射现象,文章讨论了正负折射率介质分界面的反射和折射规律,并用有限元软件Comsol Multiphysics对反射和折射现象进行仿真,同时对与理论分析一致的仿真结果以图像形式进行了显示。 相似文献
6.
7.
大气负折射现象使电磁波产生异常传播，对雷达等电子装备产生影响。论述了大气折射的基本原理、基本类型和大气负折射现象产生的机理；根据试验观测结果，应用电磁波在对流层传播的理论，利用电磁波传播损耗模式模拟电磁波在空间的传播损耗，说明了雷达等电子装备在大气负折射条件下作用距离会明显降低，提出了在登陆、航渡和布雷等海上作战中充分利用大气负折射现象的初步设想。对在作战中充分利用负折射现象有一定参考意义。 相似文献
8.
探地雷达(GPR)是近些年来比较流行的一种工程和地球物理探测方法。利用数值模型来模拟复杂的地下电磁特性模型是探地雷达理论研究的主要内容之一。论文利用复坐标延伸变量和递归卷积技术的完全匹配层吸收边界条件,构造了模拟基于表面反射GPR模型和垂直探测雷达(VRP)模型的高阶时域有限差分方法(FDTD);并对该方法的稳定性条件进行了理论和数值实例的分析。根据典型探地雷达模型仿真的正演剖面图,可观察到电磁波在地下分层介质中的传播规律,以及电特性参数对电磁波传播的影响。 相似文献
9.
通常具有负介电常数和负磁导率的左手材料是用三维金属周期结构来合成的,文章详述了在普通的微带传输线中周期性加载L-C元件构造左手材料的理论依据,以及分布式与周期结构的区别,讨论了利用L-C元件构造的左手材料所具有的特性,并对其平均折射率为零的能隙作出了解释说明. 相似文献
10.
电磁波在导电媒质中传播的计算机仿真 总被引：1，自引：0，他引：1
利用有限差分离散Maxwell方程的方法,以常见的金属铜、人体肌肉、大地和蒸馏水为例,数值模拟了正弦电磁波在良导体和电介质等不同类型导电媒质中的传播情况,形成的波传播图像合理地再现了传播过程,这些图像可以帮助人们正确理解电磁波在不同类型导电媒质中的传播情况,解释现实生活中的一些现象.通过适当改变参数,可以实现不同形式的波传播规律的模拟,程序简单,方便教学应用. 相似文献
11.
Three-layer slab waveguide with left-handed materials （LHM） is discussed using the Maxwell＇s equations and their equations of dispersion relation for TM modes are obtained. By seeking the power of the slab waveguide, their equations of effective thickness for TM modes are obtained. Furthermore, the interrelated equations for right-handed materials （RHM） slab waveguide are introduced and their curves plotted. To find new properties for LHM slab waveguide, the equations and their curves for the LHM and RHM slab waveguide are compared respectively. 相似文献
12.
Analytical solution for electromagnetic scattering from a sphere of uniaxial left-handed material 总被引：2，自引：0，他引：2
INTRODUCTION The concept of left-handed materials (LHM for short, also called negative index materials) was in- troduced by Veselago (1968). An LHM has both negative permittivity and negative permeability, which makes the wave vector, the electric-field vector, and the magnetic-field vector in the LHM obey the left-hand rule. Experimental verifications for the existence of an LHM were made and its use as a perfect lens was suggested (Pendry, 2000; Shelby et al., 2001a; 2001b; Smith … 相似文献
13.
Transmission properties of fractal Cantor distribution with left-handed materials (LHM) are investigated. The transmittance
and reflectance spectra can be calculated by using the optical transmission matrix method. Comparing with the conventional
Cantor multilayers, these structures with LHM have double functions of stopbands and defects. Through adjusting the thickness
of dielectric layers, the properties of stopbands and defects can be obtained, respectively. For stopbands, a broad stopband
filter is studied. For defect modes, multi-frequencies narrow passband filters are proposed. 相似文献
14.
近年来的研究表明,左手材料的实现已成为可能.人工复合的左手材料已成为固体物理、材料科学、光学以及应用电磁学领域的重要研究课题之一.回顾左手材料的研究进展,对其独特性质、理论原理及实验制备进行详细梳理. 相似文献
15.
INTRODUCTION Left-handed materials (LHMs), first investigated theoretically by Veselago (1968), have received sub- stantial attention in the scientific and engineering communities. The unique properties of these meta- materials are promising for a diversity of microwave applications, such as new types of beam steerers, modulators, filters, superlens (Pendry, 2000), cou- plers and antenna radoms (Smith et al., 2004). Re- cently, a transmission line (TL) approach has been successfully in… 相似文献
16.
INTRODUCTION Veselago (1968) showed that if both the permit- tivity ε and the magnetic permeability μ of a material are negative, the propagation direction of an elec- tromagnetic (EM) wave will be opposite to its energy flow direction. Such media are called left-handed materials (LHMs) since the electric field E, magnetic field H, and wave vector k in these media form a left-hand triplet of vectors, instead of a right-hand triplet observed in conventional materials. For a long time, … 相似文献
17.
In the present paper, a dynamic plastic damage model for concrete has been employed to estimate responses of a reinforced concrete slab subjected to blast loading. The interaction between the blast wave and the concrete slab is considered in 3D simulation. In the first stage, the initial detonation and blast wave propagation is modelled in 2D simulation before the blast wave reaches the concrete slab, then the results obtained from 2D calculation are remapped to a 3D model. The calculated blast load is compared with that obtained from TM5-1300. Numerical results of the concrete slab response are compared with the explosive test carried out- in the Weapons System Division, Defence Science and Technology Organisation, Department of Defence, Australia. 相似文献
18.
ZHOU Xiaoqing HAO Hong KUZNETSOV Valerian A WASCHL John 《天津大学学报(英文版)》2006,12(B09):94-99
In the present paper, a dynamic plastic damage model for concrete has been employed to estimate responses of a reinforced concrete slab subjected to blast loading. The interaction between the blast wave and the concrete slab is considered in 3D simulation. In the first stage, the initial detonation and blast wave propagation is modelled in 2D simulation before the blast wave reaches the concrete slab, then the results obtained from 2D calculation are remapped to a 3D model. The calculated blast load is compared with that obtained from TM5-1300. Numerical results of the concrete slab response are compared with the explosive test carried out-in the Weapons System Division, Defence Science and Technology Organisation, Department of Defence, Australia. 相似文献
19.
SIMOVSKI C.R VIITANEN A.J. TRETYAKOV S.A 《浙江大学学报(A卷英文版)》2006,7(1):29-33
INTRODUCTION The waveguide properties of linear arrays (chains) of silver nano-particles at optical frequencies are well known (Krenn et al., 1997; 1999; Tretyakov and Viitanen, 2000; Girard et al., 1994; Weber and Ford, 2004). Silver spheres and ellipsoids can support forward or backward waves along the chain depend- ing on their polarization state and the eigenfrequency (Krenn et al., 1999; Tretyakov and Viitanen, 2000; Girard et al., 1994; Weber and Ford, 2004). At com- paratively … 相似文献
20.
郝阳 《浙江大学学报(A卷英文版)》2006,7(1):34-40
INTRODUCTION Electromagnetic crystal structures (ECSs) offer the opportunity to control and manipulate electro- magnetic wave propagation as a result of their being formed from small-scale periodic geometric struc- tures. This detailed microscopic configuration can be designed to cause the material (macroscopically) to exhibit either effective permittivity or permeability that is negative over a finite frequency range. This modifies the dispersion relation of electromagnetic waves and a … 相似文献