共查询到17条相似文献,搜索用时 515 毫秒
1.
手征光纤中导模的色散特性 总被引:3,自引:1,他引:3
从手征介质中的电磁场本构关系出发,利用麦克斯韦方程组,对纤芯和包层都是手征介质构成的阶跃型手征光纤进行了解析求解,导出了模式场解和特征方程。用数值方法研究了纤芯和包层的手征导纳对手征光纤中导模的归一化传播常数、群延迟、波导色散等特性的影响。 相似文献
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本文用矢量有限元--边元法研究了手征波导的导波特性,与点元有限元法相比,用边元法分析手征波导模式有其明显的优越性,即不需特殊处理就可去除伪模,而且数值计算时可以节约计算机内存。本文以矩形手征波导为例,分析了全填充和部分填充手征介质时混合模的色散特性,讨论了手征导纳,波导尺寸等参量对混合模截止频率的影响,验证了边元法的有效性和正确性。 相似文献
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用多模网络与严格模匹配相结合的方法,对纵向填充一层、两层和多层手征介质的双平板中导模的反射和透射特性进行了分析和求解.分析中在横截面采用等效传输线,在纵向采用多模传输线方法,并且利用结构的对称性使得问题简化.对各种不同情形进行了数值计算,讨论了手征参数和波导结构的尺寸对反射和透射特性的影响. 相似文献
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手征介质圆波导中阶梯不连续性的散射和辐射特性研究 总被引:1,自引:0,他引:1
采用多模网络与严格模匹配相结合的方法,对开放型手征介质圆波导中的二种阶梯不连续性的散射和辐射特性进行分析和求解,仔细讨论了手征参数和几何尺寸对散射和辐射特性的影响.给出的结果对手征介质元器件的研究有实际的参考意义. 相似文献
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本文在柱坐标系中导出了手征等离子体波导内横向场量与纵向场量之间的关系,给出从向场量的波动方程,利用波导壁上的电场边界条件,建立了手征等离子体介质填充的圆波导传播常数的特征方程,计算得到了几种低次模式的传播常数随归一化波导半径及材料参数的一系列变化曲线,分析得出了若干有意义的结论。 相似文献
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本文给出了手征等离子体波导(由在柱形波导中填充手征等离子体材料构成)中横向场量与纵向场量之间的关系式,并给出了纵向场量的求解公式。作为示例,文中具体研究了平行板手征等离子体波导,得到了其中几个低次传播模式的色散特性曲线。 相似文献
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平板状双轴旋电磁手征波导中的耦合模理论 总被引:3,自引:3,他引:0
本文严格分析了一种新型双轴旋电磁手征波导中耦合模的传输特性。首先,给出了这种双各向异性手征波导中各横向场分量的纵向场分量表示式,由此得到了纵向场分量的耦合模方程,以及平板状双轴旋电磁手征波导中的色散方程。用数值方法研究了它的色散和截止特性,特别考察了双各向异性和手征性引起的波模分裂,转换效应。 相似文献
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双包层椭圆光纤的保偏特性 总被引:1,自引:1,他引:0
本文对双包层椭圆光纤进行了解析求解,得到了模式特征方程。研究了基模的保偏特性,给出了不同椭圆比下的归一化双折射和模间色散随归一化频率,纤芯内包层相对折射率差,内包层和纤芯半长轴比等参数的变化关系曲线。 相似文献
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Mook-Seng Leong Kian-Hwa Tan Le-Wei Li Pang-Shyan Kooi Tat-Soon Yeo 《Microwave Theory and Techniques》1999,47(1):74-81
For pt. I see ibid., vol. 47, no. 1, p. 67-73 (1999). A general expression of spectral-domain dyadic Green's function (DGF) in a rectangular chirowaveguide has been represented in Part I of this paper. As an application of the theory developed, this paper represents an analytic solution of electromagnetic (EM) wave propagation in the rectangular chirowaveguide. Firstly, the results of EM fields in closed form are obtained by using the DGF decomposition method, which is essentially a combination of the wavefield decomposition method followed by eigenfunction expansion of DGF. Secondly, the novel features of the analytically derived dispersion relations are analyzed and the effects of chirality on the novel features of the dispersion relations and propagation constant are discussed. Distributions of magnetic and electric fields of different order of modes are derived analytically and are then represented in vector field plots and contour plots. Also, the effects of chirality responsible for both plots are discussed. Finally, comparisons between part of the current results and those available in the literature are made. It is observed that this analysis encompasses all the published novel features for a rectangular chirowaveguide, in addition to some newly observed features. The analysis in this part of the paper confirms the applicability of the theoretical analysis given in Part I 相似文献
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The theory of chirowaveguides 总被引:13,自引:0,他引:13
The theory of chirowaveguides is discussed, and their salient features are analyzed. It is shown that the Helmholtz equations for the longitudinal components of electric and magnetic fields in chirowaveguides are always coupled and that, consequently, in these waveguides individual transverse electric (TE), transverse magnetic (TM), or transverse electromagnetic (TEM) modes cannot be supported. As an illustrative example, the parallel-plate chirowaveguide is analyzed in detail and the corresponding dispersion relations, cutoff frequencies, and propagating and evanescent modes are obtained. In the dispersion (Brillouin) diagram for a chirowaveguide, three regions are identified: the fast-fast-wave region, the fast-slow-wave region and the slow-slow-wave region. For each of these regions, the electromagnetic field components in a parallel-plate chirowaveguide are analyzed and the electric field components are plotted. Potential applications of chirowaveguides in integrated optical devices, communications systems, and printed circuit antennas are mentioned 相似文献
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Le-Wei Li Mook-Seng Leong Pang-Shyan Kooi Tat-Soon Yeo Kian-Hwa Tan 《Microwave Theory and Techniques》1999,47(1):67-73
An analytic solution of electromagnetic-wave propagation in a rectangular chirowaveguide is represented in this paper in terms of spectral-domain dyadic Green's functions (DGF's) in a general form. The method used here is a combination of a wavefield decomposition method and DGF eigenfunction expansion technique. This DGF decomposition method avoids having to use the modified and normalized vector wave functions, which are found difficult to satisfy the boundary conditions of chirowaveguides in which the reconciliation of Dirichlet and Neumann conditions is impossible. On the other hand, this method can be generalized to a chirowaveguide of arbitrary cross section and is found reducible to a nonchiral case. It is observed that in a similar fashion to the conventional rectangular waveguide, the duality between the electric and magnetic types of DGF's in the rectangular chirowaveguide does not exist. To show the reducibility of the generalized DGF's for bi-isotropic media, we summarized the procedure of utilizing the formulas and proved in detail that the form of the DGF's can be reduced to that for chiral media and achiral (isotropic) media. Exactly the same DGF's are obtainable for the isotropic media by reducing the general formulas. The electric and magnetic fields in the rectangular chirowaveguide due to a point dipole excitation oriented in the y-direction are derived. The detailed numerical analysis includes the novel features of the dispersion relations, the effects of chirality on the novel features of the rectangular chirowaveguides, some newly discovered features, and vector field plots and contour plots of higher order modes of electric and magnetic fields 相似文献
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Jin-Ping Xu 《Journal of Infrared, Millimeter and Terahertz Waves》1996,17(1):193-203
A chiroferrite is made from chiral objects immersed in a magnetically biased ferrite. A waveguide including a chiroferrite is anticipated to possess some novel features due to the presence of chirality in combination with anisotropy. In this paper, the propagation characteristics of a circular metal waveguide filled with a chiroferrite medium are investigated by an analytical procedure. The equations of relations between the transverse components and the longitudinal ones of electromagnetic fields in general chiroferrite waveguides are derived in a cylindrical coordinate system. The coupled wave equations for the longitudinal electric and magnetic fields are decoupled into two Helmholtz equations which are then solved analytically. The characteristic equation is formulated for the circular chiroferrite waveguide. Propagation constants varying with the structural and material parameters have been calculated for several lower chiral modes. A number of interesting features have been revealed by the numerical results. 相似文献
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A formally exact full-wave solution is presented for the problem of scattering at a nonchiral-chiral interface in a coaxial waveguide. The field components for the axisymmetric modes in a coaxial chirowaveguide are initially obtained. A new orthogonality relation for the modes is then proposed and used to find expansion coefficients for the electromagnetic fields in the coaxial chirowaveguide. The scattering matrix for the nonchiral-chiral dielectric discontinuity in a coaxial waveguide is finally derived by enforcing the continuity conditions of the tangential field components across the interface. Numerical results for the reflection and transmission coefficients at the nonchiral-chiral interface in a coaxial waveguide are presented 相似文献
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椭圆光波导解析解及第一个高阶模的截止频率研究 总被引:8,自引:1,他引:7
本文对椭圆光波导进行了严格的求解,得到了模场的精确解析解,导出了模式特征方程,并且证明了圆光波导仅是椭圆光波导的一个特例。文中还对第一个高阶模的特征方程进行一数值求解,得出不同椭圆度下的有效折射率与归一化频率的关系曲线及第一个高阶模的归一2化截止频率随椭圆比的变化。 相似文献