共查询到19条相似文献,搜索用时 93 毫秒
1.
2.
运用并矢法求解广义Helmholtz方程,结合Fourier变换、留数定理等数学处理,给出方程的并矢Green函数解析表达式;并进一步就旋波介质给出其中色散关系的另外一种求解方法. 相似文献
3.
4.
结合运动介质本构关系,运用并矢代数方法,求解运动介质中电磁场的色散关系.结果表明,波数k与波频ω之间仍然保持线性关系,其比例系数决定于波传播方向k与介质运动方向v之间的夹角θ、参考系之间的相对运动速度口以及静止介质折射率n’的大小. 相似文献
5.
6.
7.
根据矩阵Padé逼近理论,把磁化色散介质的相对磁导率张量表示成以jω为自变量的矩阵函数形式,用/t代替jω后过渡到时域,再引入离散时域移位算子代替时间微分算子.进而导出磁化色散介质中的磁感应强度B和磁场强度H在离散时域的色散关系,并将其具体应用于旋磁介质,得到了这种磁化色散介质的Padé时域有限差分方法的递推表达式.作为验证,用这种方法计算了磁化铁氧体球的后向雷达散射截面,所得结果与文献结果一致.理论推导及算例表明,该方法是正确和有效的.
关键词:
各向异性介质
色散介质
矩阵Padé逼近
时域有限差分方法 相似文献
8.
利用空问诱导色散补偿介质色散 总被引:2,自引:1,他引:1
研究了超短脉冲贝塞尔光束在色散介质中的传输特性,指出空间诱导色散效应可以用来补偿介质色散作用,从而可以在色散介质中实现无衍射无色散的类时空孤子波的传输。用理论推导和数值模拟的方法得到的具有反常色散性质的空间诱导色散可以有效地补偿介质色散。数值模拟的结果表明,由于超短脉冲贝塞尔光束的无衍射无色散传输距离受到高阶色散效应和贝塞尔光束空间受限两方面的限制,无衍射无色散传输只能在有限距离内近似实现。通过增加脉冲长度可以减小高阶色散效应的影响。在传输距离小于衍射距离时,空间诱导色散效应可以很好地描述脉冲演化和色散补偿过程。 相似文献
9.
10.
色散介质的介电系数是频率的函数,使本构关系在时域成为卷积关系.这就给用时域有限差分方法计算色散介质中波的散射和传播带来了困难.现有算法往往要针对不同色散介质模型推导相应的递推公式,算法的通用性较差.本文完善和发展了移位算子-时域有限差分方法,使之成为一种处理色散介质电磁问题的通用方法.首先,证明了常见的三种色散介质模型(德拜模型、洛伦兹模型和德鲁模型)的介电系数均可以写成适于移位算子法计算的有理分式函数形式.然后,用/t代替jω,过渡到时域,再引入时域移位算子zt代替时间微分算子来处理有理分式函数形式的介电系数,给出离散时域本构关系的表示式,进而导出时域有限差分方法当中电位移矢量和电场强度之间的关系.最后,计算了几种色散介质的电磁散射,数值结果表明了本文方法和程序的通用性和正确有效性.
关键词:
时域有限差分方法
色散介质
移位算子 相似文献
11.
Hongwei Yang R. S. Chen Yongchun Zhou 《International Journal of Infrared and Millimeter Waves》2007,28(9):751-758
In this paper, a novel finite-difference time-domain (FDTD) method with recursive relationships among operators is developed
for magnetized dispersive medium, named as the shift operator FDTD(SO-FDTD). The dielectric property of magnetized dispersive
medium is written as rational polynomial function, the relationship between D and E is deduced in time-domain. And its high accuracy and efficiency are verified by calculating the reflection and transmission
coefficients of electromagnetic waves through a collision plasma slab. 相似文献
12.
The possibilities of exciting equal electromagnetic fields in an isotropic chiral medium by external monochromatic electric and magnetic sources are discussed. The possibility of exciting fields that differ in a specified way is also considered. The equivalence relationships for currents and charges are determined. 相似文献
13.
The theoretical properties of a composite chiral-plasma medium are developed. By using the reaction theorem for a magnetized
chiroplasma, we obtain the proof of nonreciprocity based upon the constitutive relationships between electromagnetic vectorsE, B, H, D. Using the Maxwell’s equations and the proposed constitutive relations for a chiral-plasma medium, we derive the vectorsE andH and from these equations, dispersion relations andE-field polarizations are based. The obtained results for waves propagating parallel to the external magnetic field in a cold
magnetized chiro-plasma are compared with typical results obtained for a cold plasma. For circulary polarized waves, a new
mode conversion is founded with the chiral effect. The chiral rotation is obtained and compared with the Faraday rotation.
For waves propagating across the magnetic field, we found a shift of the cut-offs of ordinary and extraordinary waves. On
the lower branch of the extraordinary wave mode there is no bands of forbidden frequencies and the reflection point vanishes
when the chiral parameter increases. 相似文献
14.
We present a detailed study of the dispersive medium’s normal coupled modes in a symmetric one-dimensional photonic crystals (1D PCs). The splitting, homogeneous broadening effect, and the detuning effect of the normal coupled modes can be well controlled by adjusting the parameters of the dispersive medium. The bistable behavior of the PCs with Kerr medium is also investigated and it is found that the threshold intensity of nonlinear optical bistability (OB) of 1D PCs with dispersive medium is much lower than that of structure without dispersive medium. The threshold intensity is strikingly sensitive to the coupling strength of the dispersive medium. 相似文献
15.
16.
17.
采用在圆柱坐标系中分离变量的方法,推出填充多层互易手征介质的金属同轴线各层电磁场之间的关系,得到其模式特征方程和圆波导模式特征方程,给出了填充两层手征介质金属同轴线部分模式的色散特性的数值计算结果,分析了手征介质参量及两层手征介质厚度变化等对手征同轴线传播特性的影响。如果互易手征介质的手征参数等于零,可得填充普通介质的同轴线的模式特征方程。与填充普通介质的同轴线中的模式相比,手征同轴线中的模式发生了分叉。当同轴线中所填介质的折射率增大时,其模式归一化截止频率和进行基模单模传输的带宽归一化频率都将减小。 相似文献
18.
Gao Jun Guzzi Marco Nadolsky Pavel 《The European Physical Journal C - Particles and Fields》2013,73(8):1-12
The European Physical Journal C - We propose a dispersive representation of the charged pion vector form factor that is consistent with chiral symmetry and fulfills the constraints imposed by... 相似文献
19.
Slow light supported by electromagnetically induced transparency effect in dispersive medium is extremely susceptible with respect to Doppler detuning.In this paper,the Doppler effect induced by rotating dispersive medium was considered and the effect of the velocity of rotating dispersive medium on the group velocity was studied.Based on a dispersive slow-light medium,a high sensitive optical rotation sensor for measuring absolute rotation is proposed and analysed.The sensitivity of the rotation sensor is the group delay between the counterpropagationed wave packets in the device,and scales directly with square of the group index which can reach 10 2-10 8 orders of magnitude by selecting a proper dispersive medium. 相似文献