1维方形掺杂光子晶体波导中缺陷模的色散特性

为了研究1维方形掺杂光子晶体波导中缺陷模的色散,采用特征矩阵的方法研究了1维方形掺杂光子晶体波导中TE波和TM波缺陷模的变化特征,得到了TE波和TM波的缺陷模随色散强度、色散厚度变化的结果。结果表明,色散强度和色散厚度都会对1维方形掺杂光子晶体波导中TE波和TM波的缺陷模产生明显的影响;利用TE波和TM波的缺陷模随色散强度、色散厚度的变化规律,可以有效地实现对1维方形掺杂光子晶体波导中TE波和TM波各传输模式的有效控制。     

色散对圆柱形光子晶体波导传输模式的影响

利用材料的色散关系和特征矩阵法研究了一维圆柱形光子晶体波导中TE波和TM波模式禁带的变化特征,得出了TE波和TM波模式禁带随色散强度、色散厚度的变化规律.色散强度和色散厚度都会对一维圆柱形光子晶体波导中TE波和TM波的模式禁带产生影响.利用TE波和TM模式禁带随色散强度、色散厚度的变化规律,可实现对一维圆柱形光子晶体波导中TE波和TM波各传输模式的有效控制.     

波在不同色散特异介质一维光子晶体中的传播

对由两种不同色散模型的负折射特异介质构成的光子晶体,利用传输矩阵法研究了微波段的电磁波在其中传播特性.两种特异介质均为双负,TE波和TM波以相同的角度入射,有相同的带隙结构,且带隙结构对入射角不敏感.其中一种特异介质为电单负,而另一种特异介质为双负时,光子带隙对TE波的禁带随入射角的增大而展宽;而当入射角大于0.5 rad,TM波的禁带不再改变.结果表明,该结构的光子晶体带隙在某些频率内具有全向反射特性.     

光子晶体光纤中自陡效应对红移色散波的影响

基于光子晶体光纤中脉冲演变遵循的非线性薛定谔方程,用数值方法研究了三阶色散为负的情形下,自陡效应对红移色散波的影响.结果表明:由于红移色散波产生的机理不同于蓝移色散波,自陡效应对红移色散波的影响并不显著.     

二维色散介质光子晶体的能带结构求解问题研究

给出了一种计算二维色散介质光子晶体能带结构的方法，研究二维色散介质光子晶体的特性。考虑色散光子晶体，即介电常数ε=ε (ω)与频率ω相关，求解一个非线性特征值问题得到能带结构。首先，基于光子晶体电磁波传播的控制方程组推导出变分形式，对离散以后的非线性问题选择合适的解作为初始值，基于牛顿法对不同的波矢k值求解该非线性问题，获得色散关系ω(k)，从而得到光子晶体的能带结构分布。基于数值方法，求解了几种不同的色散介质光子晶体在横电（TE）、横磁（TM）模式下的能带结构，数值结果表明该方法是有效的。     

无限周期光子晶体全反射隧穿效应的色散研究

利用色散法研究了TE波和TM波在大于全反射角入射一维无限周期光子晶体的全反射隧穿特性.结果发现了一维无限周期光子晶体中的全反射隧穿效应.得出了TE波和TM波的全反射隧穿导带随入射角的变化规律,TE波和TM波的全反射隧穿导带随周期光学厚度的变化规律.     

无限周期正负折射率光子晶体的全反射隧穿效应

为了研究一维无限周期正负折射率交替结构光子晶体中光的全反射隧穿效应,利用色散法计算了TE波和TM波在大于全反射角入射一维无限周期正负折射率交替结构光子晶体的色散函数。得出了一维无限周期正负折射率交替结构光子晶体中TE波和TM波的全反射隧穿导带的频率随入射角的变化特性、全反射隧穿导带的频率随负折射材料厚度的变化特性。     

入射角度对一维光子晶体禁带的调制研究

利用特征矩阵法,分别研究了不同偏振方式的波入射到光子晶体时,光子晶体的禁带随入射角度的变化.结果表明:不论是TM波入射还是TE波入射,随着入射角度的增大,光子晶体的带隙都向短波方向移动;TM波入射时,光子晶体的带隙随入射角度的增大而减小,而以TE波入射光子晶体时,随着入射角度的增大,光子晶体的带隙逐渐增大.     

变孔径色散补偿光子晶体光纤的数值研究

文中利用有限差分法对光子晶体光纤的色散补偿特性进行了数值模拟.在常规光子晶体光纤(PCF)的基础上,变化了第二环的空气孔,增加了光子晶体光纤的结构参量变化的自由度.通过数值模拟,研究了新型光子晶体光纤包层结构参量与其色散之间的关系,并且通过优化得出低至-924.6 ps/nm/km的色散值,这在常规色散补偿光纤(DCF)中是不可能实现的.并且针对常规单模光纤色散特性,设计出合适κ值的色散补偿光子晶体光纤,色散值为-519.3 ps/km/nm,补偿能力远大于常规色散补偿光纤.     

光子晶体光纤色散特性的多极法研究

应用多极法对折射率导模型光子晶体光纤的色散特性进行了数值模拟.与实验数据对比,验证了该计算方法的准确性.研究了结构参量孔径d、孔距Λ和包层空气孔层数Nr对光子晶体光纤色散特性的影响;分析表明,通过改变包层空气孔直径d或空气孔间距Λ,可使光子晶体光纤零色散波长移动;当包层空气孔层数Nr较小时,Nr不同的各光纤色散特性差别极大;当Nr足够大时,将不再影响光子晶体光纤的色散特性.本文的计算和分析可以为设计适当色散特性的光子晶体光纤提供理论依据.     

Submillimeter wave communication versus millimeter wave communication

This paper studies the performance of a submillimeter wave antenna operating between frequencies 0.1 THz and 10 THz with a 4-cyano-4-pentylbiphenyl [5CB] substrate. Since the size and shape of the antenna impact its gain/directivity, resonant frequency, bandwidth, and efficiency, the two antenna types considered in this paper are: (a) Rectangular Patch Antenna (RPA), and (b) Cylindrical Dielectric Resonator Antenna (CDRA). Here a submillimeter wave antenna is compared with a millimeter wave (a few GHz to 100 GHz) antenna. These popular mm-wave antennas are chosen for the submillimeter wave antenna in order to understand changes in their performance as the result of changes in their geometrical shape. FEldberechnung bei Korpern mit beliebiger Oberflache (FEKO) software is used for the design and calculation of the Three-Dimensional (3D) ElectroMagnetic (EM) patterns. This paper also concentrates on the design and analysis of a massive submillimeter wave Multiple-Input Multiple-Output (MIMO) (8 by 8) RPA and CDRA.     

波浪浮标测波方法比较

波浪浮标是一种无人值守,自动检测的常用的海洋监测设备。在介绍国内外波浪浮标研究使用现状的基础上,对比分析了基于加速度传感器和GPS传感器的两种波浪浮标的共同点和不同点。     

Nonlinear wave propagation in traveling–wave amplifiers

A method is given for computing the efficiency of traveling-wave amplifiers with high gain and low C, including the effects of space charge and attenuation. The ballistics of the electrons is governed by the Boltzmann transport equation which, together with the circuit equation, is solved in a power series expansion of the input voltage. Only the first two terms of this series are computed and various nonlinear results are given in the form of curves. It appears that for small C and small convergence parameters, overtaking affects the nonlinear operation slightly.     

矩形波导中电磁波传输特性研究

本文基于功率流分别讨论了在矩形波导横截面积一定,TEm0和TMmn模式单独传输时,宽长尺寸比的最优解问题,得到了TEm0波传播时,其宽长比应趋近于0;TMmn波传播时,m＜n,仅TM12的宽长比为1;m≥n,宽长比为n/m.所得结果对矩形波导尺寸的选择和设计有潜在的应用价值.     

Magnetostatic wave convolvers

The present paper reviews recent theoretical results, and reports initial experimental results, on the convolution of contra-propagating magnetostatic forward volume waves (MSFVWs), in the form of cw signals or time-limited cw pulses, in an epitaxial yttrium iron garnet (YIG) film. Computations of the convolver bilinearity factorF _int indicate an efficient convolution process over a wide bandwidth, with values ofF _int that are of the same order as, or better than, the reported experimental results for MSW convolution in a YIG cylindrical or plate geometry. The values of F_int determined experimentally are in excellent agreement with theory. These results are of interest to microwave system developers particularly if bandwidths of 1 GHz or larger can be realized in practice. A limiting feature of magnetostatic wave (MSW) convolvers is that the maximum delay time of a delay line that is realizable without excessive insertion loss is in the order of 0.5s. The advantage of MSW convolvers, of course, lies in their ability to perform signal processing directly at microwave frequencies, and in applications such as electronic warfare the advantageously large bandwidths would mitigate the limitations in delay time.This work was supported in part by a contract from the AIL Division of the Eaton Corporation.     

Shielded rectangular dielectric wave guides for millimeter wave integrated circuits

The dispersion characteristics of Insulated non-radiative dielectric guides are computed using mode matching technique. From the dispersion characteristics the dielectric loss conductor loss and wave impedances are derived. Effect of metallic walls on trapped insulated image guide are also discussed. The dimensions of Insulated non radiative dielectric guide are same as that of rectangular metallic wave guide at ka band.     

Electrodynamics of wave processes into two-connected planar wave guide structures

There are represented three configurations of two-connected planar wave-guides, two of them have small dissipations. We research theoretically and experimentally dependences of wave impedance, integration level and dissipations of proposed waveguides on their geometrical parameters and dielectric fulfillment structure. Obtained results for planar waveguide are represented and compared with results, correspondent to standard microstrip line researches.     

Millimeter wave antennas

Major advances in millimeter-wave antennas have been made in recent years, in particular in two areas. A new class of leaky-wave antennas based on open millimeter waveguides has been proposed and investigated, and substantial progress has been achieved in integrated antennas where active and passive circuits, possibly in monolithic form, are combined with the radiating elements in one compact unit. Interesting developments have taken place also in a third group of millimeter-wave antennas, that of microstrip antennas and printed circuit antennas in general. An attempt is made to summarize these developments