Full-wave analyses of meshed-ground crossover networks by FDTD method

The finite-difference time-domain (FDTD) method is applied to the full-wave analyses of the electrical properties of meshed-ground crossover networks.     

Full-wave analysis of a new microstrip-to-waveguide interconnectconfiguration

This paper presents a new interconnect configuration between microstripline and rectangular waveguide that yields a transition from one microstripline port to two waveguide ports. Most current transitions employ only one waveguide port. Electromagnetic coupling takes place through a slot in the narrow wall of the rectangular waveguide that coincides with a slot in the ground plane of the dielectric slab. Introduction of an E-plane waveguide fin yields additional control over the insertion loss level. The numerical method employed in the analysis, which makes use of Green's function expressions in a moment-method solution, is also described and numerical details are presented. Measured results verify the accuracy of the numerical model and illustrate that it is possible to obtain insertion loss levels of 0.25 dB with this configuration. Design data and a sensitivity analysis presented here further characterize the interconnect     

Full-wave analysis of quasi-optical structures

A full-wave moment method implementation, using a combination of spatial and spectral domains, is developed for the analysis of quasi-optical systems. An electric field dyadic Green's function, including resonant and nonresonant terms corresponding to coupling from modal and nonmodal fields, is employed in a Galerkin routine. The dyadic Green's function is derived by separately considering paraxial and nonparaxial fields and is much easier to develop than a mixed, scalar and vector, potential Green's function. The driving point impedance of several antenna elements in a quasi-optical open cavity resonator and a 3×3 grid in free space are computed and compared with measurements     

Full-wave analysis of a transversely magnetized ferritenonradiative dielectric waveguide

A full-wave analysis is applied to a nonradiative dielectric waveguide where the isotropic dielectric slab is replaced by a transversely magnetized ferrite. The characteristic equation is obtained and the corresponding effects are discussed. The above structure exhibits reciprocal propagation characteristics. Nonreciprocal effects are also possible with a proper dielectric loading. Several numerical results are presented in the form of dispersion curve and an operational diagram, as a function of several ferrite and guide parameters. Electronically tuned and nonreciprocal devices can be implemented using this simple structure     

Full-wave analysis of a split-cylinder resonator for nondestructivepermittivity measurements

This paper presents a full-wave analysis of the split-cylinder resonator. We outline a model where the fringing fields are rigorously accounted for and the resonance condition is derived. Using this model, a method for nondestructively measuring the complex permittivity of materials is examined. Measurements of the complex permittivity for low-loss dielectric materials using the split-cylinder resonator agree well with measurements made in a cylindrical cavity. An uncertainty analysis for the complex permittivity is also provided     

Full-wave analysis of cross-aperture waveguide couplers

This paper presents a full-wave analysis of coupling between rectangular waveguides through a cross-aperture. The rigorous mode-matching method is used to derive the generalized scattering matrix of a waveguide T-junction having a crossed waveguide as the side arm. Two three-port T-junctions are then cascaded together to form a number of cross-aperture couplers. The analysis method can handle both broad-wall and narrow-wall, both parallel and crossed coupling structures. Our numerical results for a variety of couplers are in good agreement with those obtained by Ansoft's HFSS     

Full-wave analysis of three-dimensional planar structures

An efficient numerical-analytical approach to the analysis of planar and waveguide three-dimensional structures is presented. To maintain high accuracy and fast convergence of solutions, the technique has been based on Galerkin's method in the spectral domain. The following has been achieved: (1) formulation of a diagonalized set of integral equations for problems associated with planar structures on multilayered uniaxial dielectric substrates; (2) development and application of complete orthonormalized sets of basis functions accounting the edge conditions in explicit form; and (3) development of efficient numerical quadratures for evaluating infinite singular integrals and improvement of the convergence of the integrals and series in the matrix elements of the algebraic system     

Full-wave analysis of aperture-coupled microstrip lines

Two methods are presented for the analysis of aperture-coupled microstrip lines. Assuming a quasi-transverse electromagnetic traveling wave incident on the feeding line, an expression for the wave on the coupled line is derived. First, the moment method is used and the current on the coupled line is represented by a traveling wave propagating away from the slot. In the second method, the reciprocity theorem is applied to the coupled line. Both the moment method and the reciprocity method make use of the exact Green functions and produce results that are in very close agreement. An equivalent circuit is derived and the S-parameters are computed. Theoretical results are verified with measurements     

Full-wave analysis of microstrip floating-line discontinuities

A full-wave analysis of the resonance generated by a floating line is presented. Beginning with the dyadic Green's function for a dielectric slab, an integral equation is formulated. This integral equation is then solved by the method of moments in obtaining the transmission and reflection coefficients, as well as current distributions along the transmission line and on the floating line, both longitudinal and transverse. Employing these results, the near- and far-zone fields, as well as radiation patterns are computed. It was found that under resonance conditions the radiation power can exceed 13% of the feeding power, which may cause a potential problem in electromagnetic compatibility. Singularities involved in the Sommerfeld integrals are carried out by a novel pole extraction technique in conjunction with conventional folding methods. The new technique reduced the relative error of the singular integrals due to inaccurate pole position about one order in magnitude in comparison to the traditional approaches. To verify the new approach, a number of cases of open-ended transmission lines and gap discontinuities are examined. The results obtained from this method showed good agreement with those of previous publications     

Full-wave analysis of multilayer coplanar lines

A full-wave analysis of a coplanar waveguiding structure with multiple dielectric layers is presented. The results of a hybrid approach that combines the finite-element method and the conformal-mapping technique are compared with those of the spectral-domain approach. Numerical results for effective dielectric constants, characteristic impedances, current distributions, and field distributions for various multilayer coplanar line structures are presented and discussed. The computed results are compared with the available quasi-static ones     

Full-wave analysis of coaxial mounting structure

An efficient full-wave spectral-domain analysis based on the integral equation method is developed for a coaxial mounting structure of a general form. Using this method, the algorithm for complex input gap impedance of such structures has been derived and the calculated data are presented. The method may be useful for designing active and passive devices mounted in a coaxial line     

Full-wave spectral-domain analysis of coplanar strips

A dynamic analysis of coplanar strips (CPs) is presented. A spectral-domain stationary expression for the propagation constant has been derived making use of proven concepts of electromagnetic theory (e.g. the reaction concept). For the strip surface current distribution, which is the trial quantity in the stationary expression, a suitable approximation is used. The numerical results, obtained in a straightforward and efficient way, are in excellent agreement with results arrived at by means of more complex methods. The characteristic impedance of CPSs has been determined on the basis of two commonly used definitions. The numerical results show a novel aspect of the dynamic behavior of the impedance (power-related definition) in the upper frequency region     

角馈微带天线的全波分析

利用积分方程法对角馈型微带天线进行了分析,对其中的奇异振荡函数积分,给出了有效的数值积分方法。数值实验证明了该方法的有效性。同时,给出了角馈微带天线的输入阻抗特性,方向图特性和带宽特性。     

Full-wave analysis of dielectric frequency-selective surfaces using a vectorial modal method

A novel vectorial modal method is presented for studying guidance and scattering of frequency-selective structures based on lossy all-dielectric multilayered waveguide gratings for both TE and TM polarizations. The wave equation for the transverse magnetic field is written in terms of a linear differential operator satisfying an eigenvalue equation. The definition of an auxiliary problem whose eigenvectors satisfy an orthogonality relationship allows for a matrix representation of the eigenvalue equation. Our proposed technique has been applied to the study of lossy all-dielectric periodic guiding media with periodicity in one dimension. This method yields the propagation constants and field distributions in such media. The reflection and transmission coefficients of a single layer under a plane-wave excitation can be obtained by imposing the boundary conditions. Study of the scattering parameters of the whole multilayered structure is accomplished by the cascade connection of components as characterized by their scattering parameters. Results obtained with this method for the propagation characteristics of a one-dimensional periodic dielectric medium are compared with those presented by other authors, and results for the scattering of several dielectric frequency-selective surfaces (DFSS) are compared with both theoretical and experimental results presented in the literature, finding a very good agreement. A symmetrical band-stop filter with a single waveguide grating is also demonstrated theoretically.     

一种宽频带圆柱共形微带天线全波分析和设计

采用双层介质双贴片结构展宽天线的阻抗带宽,并利用小的贴片电容补偿由厚介质衬底引起的探针电感效应,进一步扩展了频带宽度.基于共形FDTD法结合圆柱分层媒质中并矢格林函数的新方法,对此类天线的近场和远场特性进行了严格的全波分析.提出了系统的设计流程,使得天线的设计过程变得简单易行.设计和仿真结果表明,在不增加剖面厚度的情况下,工作于L和C波段的天线带宽(VSWR≤2.0)可达近30%甚至更宽.     

Full-wave analysis of planar stratified media with inhomogeneouslayers

In this paper, the dyadic Green's functions for an inhomogeneous isotropic grounded slab embedded in an unbounded isotropic half-space fed by an electric three-dimensional (3-D) point-source based on the equivalent two-port circuit representation along the axis normal to the stratification is presented. The working case is extensively investigated by deriving important information on the radiation of the structure and on how to control the radiation on the horizon plane. Numerical results are also presented showing the effects of the electromagnetic parameters on radiation pattern of the integrated structure     

Full-wave, finite element analysis of irregular microstripdiscontinuities

Finite-element expansion currents are used to formulate a full-wave analysis of microstrip discontinuities. With this approach, a rigorous analysis of fairly irregular structures is possible, including radiation and surface wave effects as well as coupling between closely spaced junctions. The step, stub, and bent-stub discontinuities are analyzed using this technique. Measurements are made of three stub structures. Measured resonant frequencies agree with full-wave calculations to within 2% when the nominal measured dielectric constant and structure dimensions are used as input. Using the absolute worst case dielectric constants and dimensions as input gives an error of 3% for the low-frequency stub and less than that for the other stubs     

Full-wave analysis of a nonradiative dielectric waveguide with apseudochiral Ω-slab

This paper presents a new microwave device - a non-radiative dielectric (NRD) waveguide with a dielectric pseudochiral Ω-slab - the Ω-NRD waveguide. A rigorous full-wave analysis is presented and the modal equations for the longitudinal-section magnetic (LSM) and longitudinal-section electric (LSE) modes are derived. The dispersion curves and operational diagrams for the first hybrid LSM modes are presented. The effect of the pseudochiral Ω-medium is discussed. New interesting modal features are revealed, showing that the propagation characteristics may differ considerably from the common isotropic case     

Full-wave analysis of the annular-ring loaded spherical-circularmicrostrip antenna

In this paper, an annular-ring loaded (ARL) spherical-circular microstrip antenna is studied theoretically. The antenna is excited by a coaxial probe. The theoretical formulation is based on full-wave analysis in the spectral domain by using the vector Legendre transform and Galerkin's moment method is used for numerical calculation. Numerical results of the resonance frequencies, input impedance, voltage standing wave ratio (VSWR), and radiation characteristics are presented. It is shown that the impedance bandwidth of the spherical-circular microstrip antenna can be broadened by adding an annular-ring parasitic patch. By comparing to the single circular-patch case the spherical-circular microstrip antenna with an annular-ring parasitic patch has larger minor lobes and larger cross-polarization radiation