用电磁场算子理论分析脊波导的传输特性

该文用电磁场算子理论通过多个虚拟边界的电场和磁场的耦合求解脊波导的本征值,在此基础上讨论了脊波导的的传输特性。所采用的并矢格林函数没有奇异项,可以化为标量格林函数来表示,而且能很方便地计算,并与经典方法计算的结果进行了比较。     

球形分层媒质中并矢格林函数的求解域: 并矢格林函数快速计算*

首先,采用勒让德多项式的加法定理,对PartΙ部分得到的并矢格林函数进行化简,将双级数和形式转换成单级数和形式。然后,将场型格林函数转换成位型格林函数,将九个分量中收敛慢的TM 分量统一合并成公共的标量位函数。接着,利用球贝塞尔函数和汉克尔函数的渐近公式,导出并矢格林函数的渐近函数,以加速格林函数的收敛速度。最后,计算了球面共形微带天线的输入阻抗,与文献计算结果吻合,说明了处理的正确性和有效性。     

球状分层微带天线并矢格林函数的有效处理

采用提取格林函数渐进项的方法,成功克服了分层介质中球并矢格林函数计算无穷级数收敛慢的缺陷,提取出的级数形式的格林函数用球汉克尔函数的加法定理转换成闭合形式的格林函数,通过化简,使之与自由空间的格林函数有着相同的形式。因此,可采取相同的方式处理格林函数的奇异性,然后,采用以RWG为基函数的矩量法计算了圆形贴片与方形贴片微带天线的输入特性,并与文献结果、FEKO仿真结果比较,验证了方法的有效性和正确性。     

求解电磁场并矢格林函数的新方法

本文提出了求解电磁场边值问题的新方法:把矢量波方程的边值问题化为对应的标量波方程的边值问题加上两个附加的矢量微分运算的问题。用这种方法可以很方便地求解所有现在用并矢格林函数的本征展开法所能求得的各种并矢格林函数。可以求解用现有的方法很难求解的比较复杂系统的并矢格林函数。文中给出了加载的谐振腔的并矢格林函数就是其中的一例。     

加载矩形波导中的并矢格林函数及其应用

本文用镜像法推导出加载矩形波导中的并矢格林函数。在具体计算中,由于应用积分变换以及将多重无穷求和化为单一无穷和,极大地简化了计算,节省了计算时间。作为并矢格林函数应用的例子,给出了位于加载波导宽边上的金属球散射场的矩量解.计算结果与实验和文献的结果吻合很好。这种方法还能推广到其它波导。     

椭圆波导的并矢格林函数

本文应用算子法和并矢运算的分布理论,通过和法三种途径求解了椭圆波导并矢格林函数。文中还研究了其在有源区域的一些普遍性质,导出Maxwe11方程的边界条件的并矢形式,证明了关于椭圆波导中的横向电流源本征函数展开的完备性定理。     

用电磁场算子理论分析TEM室的传输特性

本文用电磁场算子理论通过多个虚拟边界的电场和磁场的耦合求解TEM室(TEM cell)的本征值,在此基础上讨论了TEM室的的传输特性,文中所采用的并矢格林函数没有奇异项,可以化为标量格林函数来计算,并与数值计算的结果进行了比较.     

无限大导电平面上复盖介质结构的并矢格林函数

本文用圆柱连续本征矢量波函数级数和积分形式表示的自由空间并矢格林函数构成了无限大导电平面上复盖介质结构的两种并矢格林函数。这些并矢格林函数对于求解微带天线、表面复盖介质板的缝隙天线或表面波天线都是有用的。源位于介质中的并矢格林函数(?)的表示式是     

并矢分析在电磁场求解中的应用

给出广义电磁场矢量和并矢波动方程的格林函数积分解,在物理定律和边界条件的约束下,用并矢分析的方法证明了两解的同解性,并对自由空间并矢格林函数的对称性进行了并矢分析展开验证。结合并矢分析法求解电磁场的两个应用实例,表明并矢分析法相对于传统方法具有简捷明了的特性。     

手征介质中并矢格林函数的讨论

本文讨论在手征介质中的广义矢量本征函数及并矢格林函数。已有的并矢格林函数展开式往往忽略了无旋本征函数（Ｌ）的贡献。在这篇文章中，我们首先给出矢势并矢格林函数的表达式，然后，利用手重量介质中矢势并矢格林函数与电并矢格林函数的关系求出了电并矢格林函数。     

A NEW METHOD FOR SOLVING DYADIC GREEN''''S FUNCTION OF ELECTROMAGNETIC FIELD

A new method for solving electromagnetic field boundary value problem is given.Byusing this method,the boundary value problem of the vector wave equation can be transformedinto the independent boundary value problem of scalar wave equations and the two additionalvector differential operations.All the dyadic Green's functions got by eigenfunction expansionof the dyadic Green's function can be got by this method easily and some of the dyadic Green'sfunctions for complex systems which are very difficult to get by the ordinary method have beengot by this new method.The dyadic Green's function for a dielectric loaded cavity is one of thegiven examples.     

EM analysis of a conducting scatterer in optic dielectric waveguide

A method to compute the scattered field of curved mirrors and gratings in a dielectric slab waveguide is proposed. In contrast to the beam propagation method (BPM) for this kind of problems, the method of moment is adopted. By introducing the dyadic Green's function in a slab waveguide, the electric field integral equations for induced current distribution on the conducting obstacles are derived. To improve the computational efficiency, the modified Green's function is incorporated into the computation program. With this study, the effects of grooves of gratings and the finite extent of the mirrors in dielectric waveguides can be investigated in more detail     

Electric-Type Dyadic Green's Functions for a Corrugated Rectangular Metaguide Based on Asymptotic Boundary Conditions

The Green's functions for the mixed potential electric field integral equation are derived for a rectangular waveguide with dielectric-filled corrugations supporting left- as well as right-hand propagation. Under the asymptotic boundary conditions assumption, the expressions of the Green's dyadic components can be decomposed into terms that represent conventional waveguide modes and others that represent hybrid metaguide modes. A simple approach is used to find the poles of the spectral domain expressions before obtaining the spatial domain expressions using the inverse Fourier transform. The dispersion diagram reflects very interesting characteristics for the structure and the deviation from the conventional case. The derived Green's function is verified by considering the problem of a probe excitation and comparing the input impedance obtained using a moment method procedure based on the present theory and the finite-difference time-domain method     

Electric dyadic Green's functions in the source region

A straightforward approach that does not involve delta-function techniques is used to rigorously derive a generalized electric dyadic Green's function which defines uniquely the electric field inside as well as outside the source region. The electric dyadic Green's function, unlike the magnetic Green's function and the impulse functions of linear circuit theory, requires the specification of two dyadics: the conventional dyadic G^-eoutside its singularity and a source dyadic L^-which is determined solely from the geometry of the "principal volume" chosen to exclude the singularity of G^-e. The source dyadic L^-is characterized mathematically, interpreted physically as a generalized depolarizing dyadic, and evaluated for a number of principal volumes (self-cells) which are commonly used in numerical integration or solution schemes. Discrepancies at the source point among electric dyadic Green's functions derived by a number of authors are shown to be explainable and reconcilable merely through the proper choice of the principal volume. Moreover, the ordinary delta-function method, which by itself is shown to be inadequate to extract uniquely the proper electric dyadic Green's function in the source region, can be supplemented by a simple procedure to yield unambiguously the correct Green's function representation and associated fields.     

Cylindrical vector eigenfunction expansion of Green dyadics for multilayered anisotropic media and its application to four-layered forest

A complete eigenfunction expansion of the dyadic Green's functions (DGFs) for planar, arbitrary multilayered anisotropic media using cylindrical vector wave functions is presented. These formulations are constructed based on the principle of scattering superposition. For the scattering dyadic Green's function in each layer, the scattering coefficients of TE and TM modes are determined from the boundary conditions matched at the planar interfaces. The explicit representation of the DGFs after reduction to the isotropic case agrees well with the existing results corresponding to the isotropic media. The general DGFs for multilayered anisotropic media are then reduced to those for a four-layered forest where the trunk layer is modeled as anisotropic medium. Application is further made for radio-wave propagation through forests of a four-layered geometry, whereas it is shown how these Green dyadic formulations are used in a practical way and how the field distributions due to a dipole can be obtained.     

The TE/sub 00/ waveguide mode - the "complete" story

A partial eigenfunction expansion of the electric-type dyadic Green's function used in aperture-coupled waveguide problems is discussed in connection with the traditional Green's function expansion in terms of the waveguide modes. Based on the principles of distributions, the delta-function term is extracted from a double series, resulting in the complete representation of the Green's function in the source region. This, in turn, is related to inclusion of the term with zero indices in the computation of the double-series expansion, even though it does not correspond to any waveguide mode. The effect of exclusion of this term from the series, and controversies over published results in the analysis of slotted-waveguide couplers and radiators, are illustrated.     

Hankel transform-domain analysis of scattered fields in multilayer planar waveguides and lasers with circular gratings

Radiation patterns of scattered fields with arbitrary azimuthal orders in multilayer planar waveguides and laser cavities with circularly symmetric gratings are formulated based on the volume current method. Full-wave Green's function analysis based on the integral transform method lies at the heart of this approach. Unlike the conventional approach, the dyadic Green's function relates some auxiliary fields to some auxiliary sources in the spectral domain. These auxiliary functions are defined to facilitate the spectral domain formulation in the cylindrical coordinate system and the use of transfer matrix method for obtaining a closed-form solution of the spectral Green's function in multilayer planar structures. More importantly, it is shown that the far-field pattern of the scattered field can be expressed directly in terms of the auxiliary fields in the Hankel transform domain.     

Dyadic Green's Functions for Integrated Electronic and Optical Circuits

Layered structures play an important role in both integrated microwave circuits and optical integrated circuits. Accurate prediction of device behavior requires evaluation of fields in the system. An increasingly used mathematical formulation refies on integral equations the electric field in the device is expressed in terms of the device current integrated into an electric Green's function. Details of the development of the specialized Green's functions used by various researchers have not appeared in the literature. We present the development of general dyadic electric Green's functions for layered structures; this dyadic formulation allows extension of previous analyses to cases where currents are arbitrarily directed. The electric-field Green's dyads are found in terms of associated Hertzian potential Green's dyads, developed via Sommerfeld's classic method. Incidently, boundary conditions for electric Hertzian potential are utiltzed; these boundary conditions, which have been a source of confusion in the research community, are developed in full generality. The dyadic forms derived herein are reducible in special cases to the Green's functions used by other workers.