各向异性磁化等离子体的ZT-FDTD算法

把运用于处理各向同性媒质的基于z变换形式的时域有限差分(ZT-FDTD)方法进行拓展,用它处理了各向异性磁化等离子体的电磁问题,给出了该方法用于各向异性磁化等离子体的递推计算公式,计算了各向异性磁化等离子体层对电磁波的反射系数和透射系数,计算结果与解析解及分段线性递归卷积FDTD(PLRC-FDTD)方法结果比较,吻合很好,从而验证了该方法用于各向异性磁化等离子体的高效性和高精度.最后,用此方法计算了各向异性磁化等离子体圆柱的后向散射宽度.该文研究结果可应用于等离子体天线等领域.     

电磁波在任意磁偏角等离子体中的传播

本文将电流密度卷积时域有限差分（Current Density Convolution Finite Difference Time Domain,JEC-FDTD）方法扩展到求解任意磁偏角电磁波在磁化等离子体中的传播和共振吸收问题.首先,验证数值算法正确性,分析了法拉第旋转角效应,以及任意磁偏角电磁波在等离子体中的传播特性.然后,求解电磁波在磁化等离子体中的等离子体朗缪尔共振、电子回旋共振、高频混杂共振吸收特性.结合在电离层加热中的应用,重点分析了等离子体高频混杂共振吸收特性,得到了高频混杂共振激发的频率匹配条件.数值结果表明,高频混杂共振吸收是电离层加热的有效方式,对于解释电离层加热机制具有重要意义.     

垂直入射空变等离子体光子晶体带隙特性研究

采用改进的磁化等离子体电磁散射的时域有限差分(FDTD)算法,分别研究了一维空变磁化和非磁化等离子体光子晶体(PPC)的禁带特性.以微分高斯脉冲为激励源,计算了等离子体光子晶体的反射系数和透射系数.讨论了在垂直入射情况下等离子体频率随空间呈脉冲形式变化的周期函数对禁带的影响.结果表明:通过改变等离子体频率在空间的不同变化可以实现对禁带的控制.     

SO-FDTD法计算磁化等离子体层的反射透射系数

从磁化等离子体的介电系数张量出发,推导出电磁波垂直入射磁化等离子体层且背景磁场沿入射方向情况时的移位算子(Shift operator,SO)FDTD迭代公式.应用该方法计算了磁化等离子体层的反射透射系数,其结果和应用传播矩阵(Propagation Matrices,PM)法及Appleton方程的计算结果符合得很好.最后,分析了背景磁场对磁化等离子体层中两个本征波即左旋和右旋波传播带的影响.     

温度、密度对磁化等离子体光子晶体的影响

为了研究温度、密度对磁化等离子体光子晶体禁带特性的影响,采用在等温近似的条件下,磁化等离子体的分段线形电流密度卷积时域有限差分算法研究了1维磁化等离子体光子晶体的禁带特性.以高斯脉冲为激励源,用算法公式得到的电磁波透射系数来讨论了温度、等离子体层密度对其禁带特性的影响.结果表明,改变温度和等离子体层密度分布可以实现对禁带的控制.     

1维时变磁化等离子体光子晶体的密温特性

为了研究1维时变磁化等离子体光子晶体禁带的温度和密度特性,采用在等温近似的条件下,磁化等离子体的分段线形电流密度卷积时域有限差分算法研究了1维时变磁化等离子体光子晶体的禁带特性。以高斯脉冲为激励源,用算法公式得到的电磁波透射系数来讨论了等离子体上升时间、温度、等离子体层密度对其禁带特性的影响。结果表明,改变等离子体上升时间和等离子体层密度可以实现对禁带的控制。这一结果对设计磁化等离子体光子晶体器件有帮助。     

温度、密度对磁化等离子体光子晶体的影响

为了研究温度、密度对磁化等离子体光子晶体禁带特性的影响,采用在等温近似的条件下,磁化等离子体的分段线形电流密度卷积时域有限差分算法研究了1维磁化等离子体光子晶体的禁带特性。以高斯脉冲为激励源,用算法公式得到的电磁波透射系数来讨论了温度、等离子体层密度对其禁带特性的影响。结果表明,改变温度和等离子体层密度分布可以实现对禁带的控制。     

基于等离子体反射特性的雷达诱饵技术研究

在研究等离子体与电磁波相互作用的基础上,得到了均匀非磁化等离子体对入射电磁波的反射系数,通过对反射特性的分析,讨论了等离子体用作雷达诱饵的有关问题．     

电磁波在磁化等离子体上的反射特性研究

研究了垂直入射的平面电磁波在分层均匀磁化等离子体中的传播规律,对包覆在金属平板表面的一维线性非均匀磁化等离子体层的反射系数进行了数值计算,并对计算结果进行了讨论。     

1维3元非磁化等离子体光子晶体禁带特性研究

为了研究1维3元非磁化等离子体光子晶体的禁带特性,采用传输矩阵法仿真计算了电磁波在1维3元非磁化等离子体光子晶体的传播规律,用计算得到的电磁波透射系数讨论了周期常数、介电常数、介质层厚度和等离子体参量对其禁带特性的影响。结果表明,改变介电常数、介质层厚度和等离子体频率可以实现对带隙的调制,增加周期数和等离子体频率不能实现对禁带的拓展。这一结果为设计1维3元非磁化等离子体光子晶体器件提供了理论参考。     

旋转四磁极磁化场及铁氧体波导系统分析

依据对旋转四磁极磁化场的物理要求，按函数逼近理论给出了磁化场及其激励源的解析表达式。利用耦合波理论和网络理论相结合的方法，系统分析了旋转四磁极磁化铁氧体波导系统的传输特性及其应用。     

SO-FDTD Analysis on Magnetized Plasma

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.     

有耗介质中的磁化等离子体波导

本文分析了有耗介质中磁化等离子体波导的传播特性。重点讨论波导衰减常数随等离子体参数和介质参数的变化。分析的结果表明．强磁场中的等离子体波导与无外磁场时的等离子体被导具有一些截然不同的传播特性。     

Microwave Characterization of Partially Magnetized Ferrites

In order to assist the microwave engineer in predicting the performance of partially magnetized devices, we have characterized the microwave permeability of partially magnetized materials. The real part of the tensor permeability elements, /spl mu/, /spl kappa/, and /spl mu//sub z/, depends primarily on the parameters /spl gamma/4/spl pi/M//spl omega/ and /spl gamma/4/spl pi/M/sub s/ / /spl omega/. Empirical formulas have been developed which show the dependence. At frequencies sufficiently below /spl omega/ = /spl pi/4/spl pi/M/sub s/, the loss can be characterized by the value of /spl mu/' at 4/spl pi/M = 0./spl mu/, /spl kappa/, and /spl mu//sub z/ depend weakly on composition, whereas /spl mu/' (4/spl pi/M = 0) does depend upon the chemical composition.     

Propagation in Longitudinally Magnetized Ferrite-Loaded Waveguide

Longitudinally magnetized reciprocal ferrite phase shifters have shown anomalous behavior in that some devices show increasing phase shift with increasing applied field, while others show decreasing phase shift with increasing applied field. This anomaly has been investigated theoretically by using a ferrite-filled parallel plane guide model. It is shown that for electrically thin guides the phase shift decreases with applied magnetic field, whereas with increased thickness, the phase shift becomes an increasing function of the applied field. The microwave electric and magnetic fields were calculated for various applied field values and reduced guide thicknesses. This showed that there are two competing mechanisms which govern the type of phase shift. These can be termed /spl mu/-effective" and "Faraday rotation." The latter sets in when the guide is thick enough to support a cross-polarized electric field of the same order of magnitude as the incident electric field. Similar analysis of the quasi-TE/sub 1/ and TM/sub 1/ modes were made, showing similar behavior at higher frequencies for a given guide thickness. Experimented verification of the quasi-TM/sub 0/ mode was made by observing transmission resonances versus applied field of resonated sections of ferrite-loaded reduced height guide.     

Propagation in Ferrite-Filled Transversely Magnetized Waveguide

A solution to the problem of propagation of higher modes in a transversely magnetized ferrite-filled rectangular waveguide has been found. The solutions to the problem are expressed in the form of four rigorous nonlinear algebraic equations which characterize the problem and are ready for numerical solution. The dependence of the fields in the direction of magnetization is the same as for the classical modes.     

Magnetostatic Waves in a Normally Magnetized Waveguide Structure

In this paper, the propagation of magnetostatic waves (MSWS) in a normally magnetized low-loss ferrite slab (such as a yttrium iron garnet (YIG) slab) placed inside a waveguide is investigated theoretically. This case has never been studied before, and is analyzed here for tbe first time. A dispersion relation for the modes of propagation in terms of an infinite determinant can be obtained. With proper truncation procedures, sample numerical calculations for dispersion relations and group time delay per unit length were obtained and are presented herein. The general formulation in this paper contains all the information provided by the degenerate cases previously published. One special case of interest, i.e., that of a multilayer planar structure, is derived from our general formulation. The derivations of other special cases follow the same procedure.     

Perturbation Analysis of Rectangular Waveguide Containing Transversely Magnetized Semiconductor

The boundary value problem of rectangular waveguide, filled with transversely magnetized semiconductor or plasma, is solved by a perturbation method reported earlier. The solution by first-order theory is compared to the results of an experiment in which surface currents in the guide wall due to perturbed and unperturbed TE/sub 1,0/ wave in N-type Silicon are sampled and segregated. Theoretical and experimental results are in excellent agreement.     

Excitation of Bulk-wave on Columns of Magnetized Plasma†

The excitation of the bulk-wave mode on a column of magnetized plasma by a ring of magnetic current outside the plasma is studied. The analysis is based on a solution of the inhomogeneous wave equation by the method of Fourier transforms. It is shown that slow waves with a large E _s field on the axis can be excited with high excitation efficiency.