共查询到19条相似文献,搜索用时 730 毫秒
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通过转移矩阵方法理论,研究含左手材料平板波导导波模式与表面波的特性,结果表明:在TE极化情况下,当包裹层为金属-芯层为左手材料的三层平板波导满足波导导行条件时,导波层能承载新功能的导波模式,即不存在TE0模;在特殊条件下存在TE1模,而且这导波模式与电磁波频率、材料的介电常数和磁导率密切相关;当不满足波导导行条件时,三层平板波导的三个区域出现不同指数规律衰减的表面波,当导波系数与导波层厚度的乘积为2.1π时,不同模式的表面波将趋向一致.模系数m的奇偶性对导波模式和表面波的能流分布有着显著的影响.利用包裹层为金属-芯层为左手材料三层平板波导的导波模式、表面波和能流分布的奇异特性,可以实现特效导波模式的波导器件,为波导实际设计和应用提供了理论参考. 相似文献
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详细研究了衬底或者覆盖层是左手材料两种情况下,空心平板波导中的表面模.引入归一化频率、归一化传播常数和非对称量等参数,得到用归一化参数表示的色散关系.用解析法计算了色散曲线,结果表明,材料参数对左手材料空心平板波导色散特性的影响很大.有的情况下只有表面TE1模存在,有的情况下只有表面TE0模存在,而有的情况下表面TE0模和表面TE1模都存在.分别讨论了TE表面模和TM表面模. 相似文献
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引入归一化频率、归一化传播常数和非对称量等参数,研究了衬底是左手材料的介质平板波导中的表面模,得到用归一化参数表示的色散关系.用解析法计算了色散曲线,结果表明,材料参数对左手材料平板波导色散特性的影响很大.有的情况下只有TE1表面模存在,而有的情况下TE0表面模和TE1表面模都存在.有时TE1表面模与零阶振荡模圆滑连接,形成一个完整的曲线,有时会出现双重简并现象.分别讨论了TE表面模和TM表面模. 相似文献
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含左手材料和单负材料三层平板波导中TE模的传输特性 总被引:1,自引:0,他引:1
研究了以左手材料为衬底和单负材料为覆盖层三层平板波导中TE模的传输特性,为波导器件的设计提供理论支持。首先导出了归一化有效厚度H与归一化频率ν的关系,然后数值计算分析了三层平板波导的传输特性。结果表明,该三层平板波导TE模具有以下特性:1)当导波层与衬底或覆盖层磁导率的比值的增大时,归一化有效折射率b随频率ν的变化率减小。2)当不对称因子a趋近于0时,b随ν单调变化;当a较大时,在截止频率附近,TE1、TE2、TE3、TE4和TE5模出现双值现象。3)当a增大时,H-ν曲线从左向右移动。4)对于TE0模,H出现负值。 相似文献
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《电子科技文摘》2006,(12)
0632385左手系材料对称平板结构中的波导模[刊,中]/王兴林//量子电子学报.-2006,23(5).-719-724(L)考虑由左手系材料作覆层衬底的对称波导系统,研究了TE线性极化波在该波导中的传播特性。利用直接图解法对各种波导模式进行了详细地判别.结果表明快波、慢波均可以在该波导中传播。两者的模式特征与传统介电波导及左手波导均存在较大差异。分析了导波的色散关系并定性地讨论了群速度随频率的变化规律。揭示了在一定条件下,该波导系统既可以支持前向线性TE波的传播也可以支持反向线性TE波的传播,且支持低阶快波偶模式和慢波奇模式传播的频率段相对狭窄。参13 相似文献
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5层金属包覆介质波导的模式特性研究 总被引:1,自引:1,他引:0
采用有限元方法(FEM)对具有复折射率的金属包覆5层平板波导和矩形波导的折射率及模场分布进行了求解并进行了定性的分析。得到了5层平板波导的模折射率随芯层厚度、缓冲层厚度和金属层厚度的变化关系;给出了等离子体表面模的模场分布演变,揭示了在缓冲层变化时等离子体表面波向普通TM模式及低阶TM模向高阶TM模的演变过程:计算了二维结构5层矩形波导的模折射率随缓冲层厚度、芯层厚度和芯层宽的变化关系。结果表明,在二维结构的金属包覆波导中存在多种等离子体表面模,在缓冲层的变化过程中其TM模同样存在模式转变过程。并给出了部分等离子体表面模的模场分布;在金属层的影响下,TM模式的模场分布受到扰动,并给出了受扰动的低阶TM模的模场分布。 相似文献
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A symmetric five-layer slab waveguide with anisotropic and dispersive left-handed material (LHM) in the core and righthanded
material (RHM) in other layers is investigated. Through Maxwell’s equations and a transfer matrix method, the dispersion equations
for the TE oscillating guided modes are obtained. Under consideration of two extremely anisotropic cases, some mode dispersion
curves are plotted. The zero-order TE oscillating guided mode exists. Meanwhile, with the increase of mode number, their dispersion
curves move to left or right, corresponding to positive or negative dielectric permittivity and magnetic permeability in the
longitudinal direction. Besides, as the core thickness increases, mode dispersion properties change and three propagation
properties appear: positive group velocity, negative group velocity and zero group velocity. The negative group velocity indicates
the characteristics of the left-handed materials, and the zero group velocity implies that electromagnetic waves are trapped
in the waveguide completely. 相似文献
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《Microwave Theory and Techniques》1981,29(2):107-114
The reflection and the scattering properties of even TE and TM surface waves incident in an abruptly ended dielectric slab waveguide are analyzed. The discontinuity is regarded as a junction between two open waveguides namely the dielectric slab waveguide and the free space waveguide. The boundary conditions acting together with the orthogonality provide singular coupled integral equations on the discrete and the continuous wave amplitudes at the discontinuity. These singular coupled intergral equations with Cauchy kernels and infinite limits of integration are solved by iteration via the Neuman series. Numerical results are presented for the reflectivity of the even TE/sub 0/ and TM/sub 0/ fundamental modes, together with their mode conversion on even TE/sub 2/ and TM/sub 2/ in a slab where two guided modes can propagate. Reflectivity and mode conversion of higher order excitations are also investigated 相似文献
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《Photonics Technology Letters, IEEE》2009,21(11):736-738
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《Microwave Theory and Techniques》1978,26(11):919-919
In the above paper/sup1/, Magerl derives dispersion equations for TE/sub m0/ modes of ridged waveguide with inhomogeneous dielectric-slab loading. The existence of TE modes was evidently assumed a priori (a seemingly natural assumption); unfortunately, true TE modes do not exist in this waveguide (with a singuIar exception to be noted). 相似文献
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A multilevel grating coupler based on silicon-on-insulator (SOI) material structure is proposed to realize the coupling between waveguide and waveguide or waveguide and fiber. This coupler is compatible with the current fabrication facilities for complementary metal oxide semiconductor (CMOS) technology with vertical coupling. This structure can realize coupling when the beams with transverse electric (TE) polarization and transverse magnetic (TM) polarization are incident at the same time. The influences of the grating coupler parameters including wavelength, the thickness of waveguide layer, the thickness of SiO2 layer and the number of steps on the TE mode and TM mode coupling efficiencies are discussed. Theory researches and simulation results indicate that the wavelength range is from 1533 nm to 1580 nm when the TE mode and TM mode coupling efficiencies are both more than 40% as the grating period is 0.99 μm. The coupling efficiencies of the incident TE and TM modes are 49.9% and 49.5% at the wavelength of 1565 nm, respectively, and the difference between them is only 0.4%. 相似文献
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《Microwave Theory and Techniques》1965,13(5):641-646
The characteristics of electromagnetic waves propagating in a semiconductor filled rectangular waveguide in the presence of a transverse magnetic field are studied. It is shown that only TE mode waves having y-independent field components (y being the direction of the steady magnetic field) and anomalous modes having all six field components can propagate. The propagation constant of waves characterized by a sinusoidal y dependence of fields is derived. Asymptotic expressions for the fields and the propagation constant are then obtained for the limiting case of a small external magnetic field and some recent experimental results are analyzed in this context. 相似文献
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《Microwave Theory and Techniques》1972,20(3):210-214
An analysis of the modes that can propagate in a coaxial waveguide with Iossless reactive guiding surfaces is presented. The cases where both the surfaces are either inductive or capacitive and the case where one of the surfaces is capacitive and the other is inductive are discussed. The results show that, in general, there are two surface waves and an infinite number of waveguide modes. Whereas all the waveguide modes show the cut off phenomenon, the surface waves may either propagate down to zero frequency or get transformed into the lowest order waveguide mode at certain critical frequencies determined by the structure parameters. 相似文献
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The dispersion properties of the guided modes propagating along a dielectric slab waveguide with a left-handed material substrate are studied. It is shown that both the oscillating and surface modes can propagate very slowly along such a waveguide if the thickness of the core layer is chosen appropriately. The propagation speed of the guided waves can even approach zero and this slow propagation is illustrated with an finite-difference time-domain simulation in a tapered waveguide. The influence of the material loss on the slow propagation is also discussed. 相似文献