Showing papers on "Computational electromagnetics published in 2002"
TL;DR: A convergent high-order accurate scheme for the solution of linear conservation laws in geometrically complex domains and demonstrates the versatility, flexibility, and robustness when solving two- and three-dimensional benchmark problems in computational electromagnetics.
763 citations
Book•
08 May 2002
TL;DR: In this article, the authors present a generalization of the Backus-Gilbert method for linear inverse problems in the context of geophysics, which is based on the theory of functions of a complex variable.
Abstract: Preface. I. Introduction to Inversion Theory. 1. Forward and inverse problems in geophysics. 1.1 Formulation of forward and inverse problems for different geophysical fields. 1.2 Existence and uniqueness of the inverse problem solutions. 1.3 Instability of the inverse problem solution. 2. Ill-posed problems and the methods of their solution. 2.1 Sensitivity and resolution of geophysical methods. 2.2 Formulation of well-posed and ill-posed problems. 2.3 Foundations of regularization methods of inverse problem solution. 2.4 Family of stabilizing functionals. 2.5 Definition of the regularization parameter. II. Methods of the Solution of Inverse Problems. 3. Linear discrete inverse problems. 3.1 Linear least-squares inversion. 3.2 Solution of the purely under determined problem. 3.3 Weighted least-squares method. 3.4 Applying the principles of probability theory to a linear inverse problem. 3.5 Regularization methods. 3.6 The Backus-Gilbert method. 4. Iterative solutions of the linear inverse problem. 4.1 Linear operator equations and their solution by iterative methods. 4.2 A generalized minimal residual method. 4.3 The regularization method in a linear inverse problem solution. 5. Nonlinear inversion technique. 5.1 Gradient-type methods. 5.2 Regularized gradient-type methods in the solution of nonlinear inverse problems. 5.3 Regularized solution of a nonlinear discrete inverse problem. 5.4 Conjugate gradient re-weighted optimization. III. Geopotential Field Inversion. 6. Integral representations in forward modeling of gravity and magnetic fields. 6.1 Basic equations for gravity and magnetic fields. 6.2 Integral representations of potential fields based on the theory of functions of a complex variable. 7. Integral representations in inversion of gravity and magnetic data. 7.1 Gradient methods of gravity inversion. 7.2 Gravity field migration. 7.3 Gradient methods of magnetic anomaly inversion. 7.4 Numerical methods in forward and inverse modeling. IV. Electromagnetic Inversion. 8. Foundations of electromagnetic theory. 8.1 Electromagnetic field equations. 8.2 Electromagnetic energy flow. 8.3 Uniqueness of the solution of electromagnetic field equations. 8.4 Electromagnetic Green's tensors. 9. Integral representations in electromagnetic forward modeling. 9.1 Integral equation method. 9.2 Family of linear and nonlinear integral approximations of the electromagnetic field. 9.3 Linear and non-linear approximations of higher orders. 9.4 Integral representations in numerical dressing. 10. Integral representations in electromagnetic inversion. 10.1 Linear inversion methods. 10.2 Nonlinear inversion. 10.3 Quasi-linear inversion. 10.4 Quasi-analytical inversion. 10.5 Magnetotelluric (MT) data inversion. 11. Electromagnetic migration imaging. 11.1 Electromagnetic migration in the frequency domain. 11.2 Electromagnetic migration in the time domain. 12. Differential methods in electromagnetic modeling and inversion. 12.1 Electromagnetic modeling as a boundary-value problem. 12.2 Finite difference approximation of the boundary-value problem. 12.3 Finite element solution of boundary-value problems. 12.4 Inversion based on differential methods. V. Seismic Inversion. 13. Wavefield equations. 13.1 Basic equations of elastic waves. 13.2 Green's functions for wavefield equations. 13.3 Kirchhoff integral formula and its analogs. 13.4 Uniqueness of the solution of the wavefield equations. 14. Integral representations in wavefield theory. 14.1 Integral equation method in acoustic wavefield analysis. 14.2 Integral approximations of the acoustic wavefield. 14.3 Method of integral equations in vector wavefield analysis. 14.4 Integral approximations of the vector wavefield. 15. Integral representations in wavefield inversion. 15.1 Linear inversion methods. 15.2 Quasi-linear inversion. 15.3 Nonlinear inversion. 15.4 Principles of wavefield migration. 15.5 Elastic field inversion. A. Functional spaces of geophysical models and data. A.1 Euclidean space. A.2 Metric space. A.3 Linear vector spaces. A.4 Hilbert spaces. A.5 Complex Euclidean and Hilbert spaces. A.6 Examples of linear vector spaces. B. Operators in the spaces of models and data. B.1 Operators in functional spaces. B.2 Linear operators. B.3 Inverse operators. B.4 Some approximation problems in the Hilbert spaces of geophysical data. B.5 Gram - Schmidt orthogonalization process. C. Functionals in the spaces of geophysical models. C.1 Functionals and their norms. C.2 Riesz representation theorem. C.3 Functional representation of geophysical data and an inverse problem. D. Linear operators and functionals revisited. D.1 Adjoint operators. D.2 Differentiation of operators and functionals. D.3 Concepts for variational calculus. E. Some formulae and rules from matrix algebra. E.1 Some formulae and rules of operation on matrices. E.2 Eigenvalues and eigenvectors. E.3 Spectral decomposition of a symmetric matrix. E.4 Singular value decomposition (SVD). E.5 The spectral Lanczos decomposition method. F. Some formulae and rules from tensor calculus. F.1 Some formulae and rules of operation on tensor functions. F.2 Tensor statements of the Gauss and Green's formulae. F.3 Green's tensor and vector formulae for Lame and Laplace operators. Bibliography. Index.
709 citations
Book•
01 Oct 2002
TL;DR: In this article, a method of moments (MoM) was proposed for electromagnetic modeling of composite metallic and dielectric structures using entire-domain basis functions defined over bilinear surfaces, resulting in a remarkably small number of unknowns.
Abstract: Starting from the equivalence theorem any composite metallic and dielectric structure can be analyzed by using SIE (surface integral equations). Such integral equations are usually solved by MoM (method of moments). Most of the existing MoM methods for solving SIE are developed for BORs (bodies of revolution). There are only few such methods that can handle structures of arbitrary shape. These methods use sub-domain basis functions defined over triangles, requiring a very large number of unknowns even for the simplest problems. This paper presents a new MoM method for electromagnetic modeling of composite metallic and dielectric structures. The method uses entire-domain basis functions defined over bilinear surfaces, resulting in a remarkably small number of unknowns.
439 citations
TL;DR: An overview of MAS as applied to computational electromagnetics can be found in this article, where a selection of recent developments in the method is presented, with a detailed description of several challenging topics.
Abstract: The method of auxiliary sources (MAS) is a numerical technique, alternative to the standard surface integral-equation formulation, suitable for solving elliptic boundary-value problems appearing in electromagnetic scattering analysis, antenna modeling, waveguide structures, etc. This paper provides an overview of MAS as applied to computational electromagnetics. The fundamentals of MAS are presented and its advantages over the method of moments are highlighted, while special emphasis is given to a number of advanced issues. Moreover, a selection of recent developments in the method is presented, with a detailed description of several challenging topics. Finally, the potential applicability of the method to a broader range of problems is contemplated.
183 citations
TL;DR: A new version of the combined field integral equation (CFIE) for the solution of electromagnetic scattering problems in three dimensions is introduced, meaning that it is a second kind integral equation that does not suffer from spurious resonances and does not become ill conditioned for fine discretizations.
Abstract: We introduce a new version of the combined field integral equation (CFIE) for the solution of electromagnetic scattering problems in three dimensions. Unlike the conventional CFIE, the new CFIE is well-conditioned, meaning that it is a second kind integral equation that does not suffer from spurious resonances and does not become ill conditioned for fine discretizations (the so-called "low-frequency problem"). The new CFIE combines the standard magnetic field integral operator with an analytically preconditioned electric field integral operator. We also report numerical results showing that the new formulation stabilizes the number of iterations needed to solve the CFIE on closed surfaces. This is in contrast to the conventional CFIE, where the number of iterations grows as the discretization is refined.
182 citations
TL;DR: This paper demonstrates that the convergence of iterative methods can be improved significantly, if the original integral equation is replaced by an equation based on the modified Green's operator with the norm less or equal to one, and called the Contraction Integral Equation (CIE) method.
Abstract: [1] The integral equation method has been proven to be an efficient tool to model three-dimensional electromagnetic problems. Owing to the full linear system to be solved, the method has been considered effective only in the case of models consisting of a strongly limited number of cells. However, recent advances in matrix storage and multiplication issues facilitate the modeling of horizontally large structures. Iterative methods are the most feasible techniques for obtaining accurate solutions for such problems. In this paper we demonstrate that the convergence of iterative methods can be improved significantly, if the original integral equation is replaced by an equation based on the modified Green's operator with the norm less or equal to one. That is why we call this technique the Contraction Integral Equation (CIE) method. We demonstrate that application of the modified Green's operator can be treated as a preconditioning of the original problem. We have performed a comparative study of the convergence of different iterative solvers applied to the original and contraction integral equations. The results show that the most effective solvers are the BIGGSTAB, QMRCGSTAB, and CGMRES algorithms, equipped with preconditioning based on the CIE method.
165 citations
TL;DR: The analysis of the long time behavior of two unsplit PML methods for the absorption of electromagnetic waves reveals that the source of the instability is the undifferentiated terms of the PML equations and that it is associated with a degeneracy of the quiescent systems of equations.
Abstract: We investigate the long time behavior of two unsplit PML methods for the absorption of electromagnetic waves. Computations indicate that both methods suffer from a temporal instability after the fields reach a quiescent state. The analysis reveals that the source of the instability is the undifferentiated terms of the PML equations and that it is associated with a degeneracy of the quiescent systems of equations. This highlights why the instability occurs in special cases only and suggests a remedy to stabilize the PML by removing the degeneracy. Computational results confirm the stability of the modified equations and is used to address the efficacy of the modified schemes for absorbing waves.
127 citations
TL;DR: A comparison between simulations with A-V formulation models implemented in two FEM software packages (FLUX2D and FLUX3D) and a numerical method based on analytical model for superconductors in applied magnetic field is presented in this article.
Abstract: Different finite-element method (FEM) formulations have been developed in order to model the electromagnetic behavior of type-II superconductors. This paper presents a comparison between simulations with A-V formulation models implemented in two FEM software packages (FLUX2D and FLUX3D) and a numerical method based on analytical model for superconductors in applied magnetic field. These models can be used for superconductors with complex geometry and power-law current-voltage characteristics. Simulated is a 37-filamentary tape with applied transport current in self-field and alternating current (ac) magnetic field parallel to the wide side of the tape. A good agreement is found between the ac-loss and current distributions obtained with the different models.
102 citations
TL;DR: In this article, a model of core-type distribution transformers for electromagnetic transient studies is proposed, which accurately reproduces not only the impedance characteristics seen from each terminal of a core type distribution transformer but also the surge-transfer characteristics between the primary and secondary sides in a wide range of frequencies.
Abstract: This paper proposes a model of core-type distribution transformers for electromagnetic (EM) transient studies. The model accurately reproduces not only the impedance characteristics seen from each terminal of a core-type distribution transformer but also the surge-transfer characteristics between the primary and secondary sides in a wide range of frequencies. Due to the above capability, the proposed model enables the accurate evaluation of overvoltages on distribution lines including consumer-side overvoltages. In this paper, a 10-kVA transformer is modeled, and transient-simulation results agree well with laboratory-test ones.
78 citations
08 May 2002
TL;DR: In this article, the modeling analysis and soft seating control of an electromagnetic actuator used in electromechanical camless valve-trains is addressed, which reveals the instability of the actuator dynamics linearized around the seating position and zero velocity.
Abstract: This paper addresses the modeling analysis and soft seating control of an electromagnetic actuator used in electromechanical camless valve-trains. Our mathematical modeling analysis reveals the instability of the actuator dynamics linearized around the seating position and zero velocity. This implies that an open loop pulse shaping alone cannot render repeatable valve closing and seating motions. Closed loop feedback control is necessary to generate repeatable motions that is insensitive to disturbances. A linear model is constructed based on a gray-box approach that combines mathematical modeling and system identification. Notch filtering and linear quadratic optimal control are designed and experimentally tested. The control performance is evaluated in terms of the closing time, valve seating velocity and seating tail-length, armature crossing velocity and armature seating velocity.
50 citations
TL;DR: In this paper, an efficient method-of-moments (MoM) solution for analysis of multilayer microstrip antennas and circuits is presented for 3D multi-layer microstrip structures.
Abstract: An efficient method-of-moments (MoM) solution is presented for analysis of multilayer microstrip antennas and circuits. The required multilayer Green's functions are evaluated by the discrete complex image method (DCIM), with the guided-mode contribution extracted recursively using a multilevel contour integral in the complex /sub /spl rho//-plane. An interpolation scheme is employed to further reduce the computer time for calculating the Green's functions in the three-dimensional (3-D) space. Higher order interpolatory basis functions defined on curvilinear triangular patches are used to provide necessary flexibility and accuracy for the discretization of arbitrary shapes and to offer a better convergence than lower order basis functions. The combination of the improved DCIM and the higher order basis functions results in an efficient and accurate MoM analysis for 3-D multilayer microstrip structures.
TL;DR: Investigation of analytical solutions for the sphere suggests the parameter range in which this approximation might perform well and suggests ways of improving accuracy over an extended range, and the fundamental TSA formulation appears to be relatively robust.
Abstract: The problem of numerical modeling of electromagnetic induction (EMI) responses by metallic objects is complicated by the fact that transmitted fields may penetrate the target, but will often only do so slightly. The effect cannot be ignored, yet it is often grossly impractical to discretize the entire surface or volume of a target in space increments only on the order of a fraction of the skin depth. To deal with this problem, we retain a simple integral equation formulation in scalar potential for the region outside the target, where magnetic fields are quasi-static and irrotational. Within the target we apply only the divergence relation, /spl nabla//spl middot/H = 0. When the skin depth is small relative to the radius of curvature of the target (e.g., <0.1), we use the thin skin depth approximation (TSA), /spl part/H/sub n///spl part/n as /spl sim/-ikH/sub n/, just inside the target's surface, where k is the electromagnetic wavenumber inside the metal and n is the normal direction on the surface and pointing inside of metallic object. Examination of analytical solutions for the sphere suggests the parameter range in which this approximation might perform well and suggests ways of improving accuracy over an extended range. The fundamental TSA formulation appears to be relatively robust. Analysis indicates that it is insensitive to variation over the target's surface of primary field orientation relative to that surface, and that it is only dependent on the target's magnetic permeability through induction number. Implementing the TSA numerically, within the above divergence relation, allows us to express all quantities in terms of tangential magnetic field components and their tangential derivatives over the target surface. In principle, this closes the system completely in terms of the exterior scalar potential. Broad-band numerical simulations based on the TSA compare favorably with analytical and other numerical solutions.
10 Nov 2002
TL;DR: FastMag as mentioned in this paper uses a magnetic surface charge formulation, efficient techniques for evaluating the required integrals, and a preconditioned GMRES method to solve the resulting linear system.
Abstract: In this paper we present a fast and efficient program for extraction of the frequency dependent inductance of structures with permeable materials. The program, FastMag, uses a magnetic surface charge formulation, efficient techniques for evaluating the required integrals, and a preconditioned GMRES (generalized minimal residual algorithm) method to solve the resulting linear system. Results from examples are presented to demonstrate the accuracy and versatility of the FastMag program.
TL;DR: In this article, the authors derived the electromagnetic field distribution on a rectangular aperture backed by rectangular cavities by using a circuital model of an aperture and suitable forcing terms introduced into the equations related to the aperture model.
Abstract: In this paper, the problem of evaluating the electromagnetic field on rectangular apertures backed by rectangular cavities is investigated. The electromagnetic-field distribution is derived by using a circuital model of an aperture and suitable forcing terms introduced into the equations related to the aperture model. The effects of a rectangular cavity on the aperture-field distribution are assessed by considering the rectangular cavity as a load impedance. The impedance value is obtained by modeling the rectangular cavity as a length of rectangular waveguide back-ended by a short. The distribution of the electromagnetic field on the aperture is used as an exciting source to evaluate, through a modal expansion, the electromagnetic field inside the cavity. Numerical simulations are in a good agreement with both other theoretical models and experimental data.
TL;DR: In this paper, a new three-dimensional (3D) MT modeling scheme conserving electric current and magnetic flux is developed, which is based on finite difference (FD) staggered rectangular non-uniform grid formulation for the secondary electric field with continuous components of tangential electric and normal magnetic fields.
Abstract: A new three-dimensional (3D) MT modeling scheme conserving electric current and magnetic flux is developed. The scheme is based on finite difference (FD) staggered rectangular non-uniform grid formulation for the secondary electric field with continuous components of tangential electric and normal magnetic fields, in contrast to existing FD algorithms with a discontinuous E-field at the face of the cells. The scheme leads to a sparse 13-band complex symmetrical system of linear equations, which is effectively solved by fast and stable conjugate gradient (CG) methods. The preconditioning procedure was used to decrease the condition of a number of an ill-conditioned matrix system by several orders and stably and quickly solves the matrix system. The special module for the correction of divergence-free current J greatly increased the speed of convergence and accuracy, especially at low frequencies and for high-contrast resistivity or conductivity structures. A special procedure was developed to improve the accuracy of tangential magnetic and vertical electrical components at the Earth’s surface and at the interface with a large conductivity contrast. The validity of the new algorithm was demonstrated for difficult models with high-contrast resistivity structures including topography and for COMMEMI project models.
TL;DR: In this paper, the authors describe a systematic methodology for the electromagnetic modeling of complex power distribution networks, using locally three-dimensional modifications to an otherwise two-dimensional (2D) description of the behavior of electromagnetic fields between power/ground plane pairs, to model correctly the field behavior at discontinuities such as vias, pins, and splits in the power and ground plane structure.
Abstract: This paper describes a systematic methodology for the electromagnetic modeling of complex power distribution networks. The proposed methodology uses locally three-dimensional (3D) modifications to an otherwise two-dimensional (2D) description of the behavior of electromagnetic fields between power/ground plane pairs, to model correctly the field behavior at discontinuities such as vias, pins, and splits in the power/ground plane structure. Furthermore, a systematic synthesis methodology is presented for the direct generation of a SPICE-compatible multiport macro-model for the power distribution network from its discrete quasi 3D model. The proposed modeling and equivalent circuit synthesis methodologies are validated through a specific numerical simulation study of the transient electromagnetic analysis of a power/ground plane pair during switching.
IMEC1
TL;DR: This paper deals with the software implementation, the treatment of interfaces and domain boundaries, scaling considerations, numbering schemes, and solver requirements on the simulation of on-chip high-frequency effects.
Abstract: This is the second paper in a series on the simulation of on-chip high-frequency effects. A computer-aided approach in three dimensions is advocated, describing high-frequency effects such as current redistribution due to the skin-effect or eddy currents and the occurrence of slow-wave modes. The electromagnetic environment is described by an electric scalar potential and a magnetic vector potential as well as a ghost field. The latter one guarantees a stable numerical implementation. This paper deals with the software implementation, the treatment of interfaces and domain boundaries, scaling considerations, numbering schemes, and solver requirements. Some illustrative examples are shown.
TL;DR: In this paper, the authors present numerical implementation of high order RWG basis functions for electromagnetic scattering for curved conductor surfaces with a procedure for treating the singularities of dyadic Green's functions in the mixed potential formulation of electromagnetic scattering.
Abstract: We present numerical implementation of high order RWG basis functions for electromagnetic scattering for curved conductor surfaces with a procedure for treating the singularities of dyadic Green's functions in the mixed potential formulation of electromagnetic scattering. Copyright © 2001 John Wiley & Sons, Ltd.
TL;DR: In this paper, a pseudospectral frequency-domain (PSFD) method was proposed for large-scale problems with a spectral accuracy of less than 1% in typical examples, where the Chebyshev polynomials were used to represent unknown field components in each subdomain.
Abstract: This letter describes a new frequency-domain method for Maxwell's equations based on the multidomain pseudospectral method. The computational domain is first divided into nonoverlapping subdomains. Using the Chebyshev polynomials to represent the unknown field components in each subdomain, the spatial derivatives are calculated with a spectral accuracy at the Chebyshev collocation points. The physical boundary conditions at the subdomain interfaces are enforced to ensure the global accuracy. Numerical results demonstrate that the pseudospectral frequency-domain (PSFD) method has a spectral accuracy, and thus is an attractive method for large-scale problems. With only about five cells per wavelength, the results have an error less than 1% in our typical examples.
TL;DR: In this article, a higher-order geometry modeling technique is presented for the solution of volume integral equations (VIEs) involving arbitrarily shaped inhomogeneous dielectric structures.
Abstract: [1] A higher-order geometry modeling technique is presented for the solution of volume integral equations (VIEs) involving arbitrarily shaped inhomogeneous dielectric structures. Conformal basis functions defined in curved hexahedral finite elements are used to develop a moment method solution of the VIE. Results are compared with available analytical solutions, and the method is shown to deliver higher accuracy using coarser meshes as compared to partial differential equation solvers. INDEX TERMS: 0619 Electromagnetics: Electromagnetic theory; 0644 Electromagnetics: Numerical methods; 0669 Electromagnetics: Scattering and diffraction
TL;DR: A novel and fast integral-equation-based scheme is presented for analyzing transient electromagnetic scattering from homogeneous, isotropic, and nondispersive bodies and results that demonstrate the accuracy and the efficacy of the scheme are presented.
Abstract: A novel and fast integral-equation-based scheme is presented for analyzing transient electromagnetic scattering from homogeneous, isotropic, and nondispersive bodies. The computational complexity of classical marching-on-in-time (MOT) methods for solving time-domain integral equations governing electromagnetic scattering phenomena involving homogeneous penetrable bodies scales as O(NtNs2). Here, Nt represents the number of time steps in the analysis, and Ns denotes the number of spatial degrees of freedom of the discretized electric and magnetic currents on the body’s surface. In contrast, the computational complexity of the proposed plane-wave–time-domain-enhanced MOT solver scales as O(NtNs log2 Ns). Numerical results that demonstrate the accuracy and the efficacy of the scheme are presented.
TL;DR: In this paper, a mathematical model for time domain simulation of electromagnetic transients in multiphase NULs taking into account the frequency dependence of the parameters is presented, which can be interfaced with time domain programs such as the EMTP.
Abstract: Transmission lines with nonparallel conductors or significant sags and vertical structures, such as towers, can be viewed and modeled as nonuniform lines (NULs). The parameters of NULs are distance dependent. This paper presents a mathematical model for time domain simulation of electromagnetic transients in multiphase NULs taking into account the frequency dependence of the parameters. The model is based on the traveling wave phenomenon and accommodates any NUL geometry. In addition, the model can be interfaced with time domain programs such as the EMTP. The proposed methodology is validated by comparing the results with those obtained from a frequency domain model using the numerical Laplace transform (LT), the method of characteristics (MC), and also with test results reported by other investigators.
TL;DR: An interactive modeling and analysis program with a user-friendly graphical interface, for students and professionals in the field of exploration geophysics, has been developed as mentioned in this paper, where the ElectroMagnetic...
Abstract: An interactive modeling and analysis program with a user-friendly graphical interface, for students and professionals in the field of exploration geophysics, has been developed. The ElectroMagnetic...
TL;DR: In this paper, a general framework of explicit Runge-Kutta and leap-frog integrators of arbitrary orders N is derived and the powerful root-locus method derived from general system theory forms the basis of the theoretical mainframe for analysing convergence, stability and dispersion characteristics of the proposed integrators.
Abstract: The finite integration technique (FIT) is an efficient and universal method for solving a wide range of problems in computational electrodynamics. The conventional formulation in time-domain (FITD) has a second-order accuracy with respect to spatial and temporal discretization and is computationally equivalent with the well-known finite difference time-domain (FDTD) scheme. The dispersive character of the second-order spatial operators and temporal integration schemes limits the problem size to electrically small structures. In contrast higher-order approaches result not only in low-dispersive schemes with modified stability conditions but also higher computational costs. In this paper, a general framework of explicit Runge–Kutta and leap-frog integrators of arbitrary orders N is derived. The powerful root-locus method derived from general system theory forms the basis of the theoretical mainframe for analysing convergence, stability and dispersion characteristics of the proposed integrators. As it is clearly stated, the second- and fourth-order leap-frog scheme are highly preferable in comparison to any other higher order Runge–Kutta or leap-frog scheme concerning stability, efficiency and energy conservation. Copyright © 2002 John Wiley & Sons, Ltd.
07 Aug 2002
TL;DR: A new generalized mode-matching (GMM) approach to both mode bases and S-matrices calculation of complicated waveguide circuits that is closer to the software based on the mesh methods in generality, in the same time saving the high accuracy and computation speed typical for highly specialized mode- matching procedures.
Abstract: The main goal of the paper is to present a new generalized mode-matching (GMM) approach to both mode bases and S-matrices calculation of complicated waveguide circuits. Development of the GMM procedures makes it possible to realize totally automatic algorithms for a wide set of configurations avoiding a specialized analytical treatment of each new boundary-value problem. Moreover, the background for linking up the interface tools of a circuit geometry specification and editing is provided by the GMM approach together with the special algorithms for recognizing the object configurations and for data preparation. The class of objects that can be calculated by the suggested approach includes any WG circuits with metal boundaries specified in the Cartesian coordinate system or with the smooth boundaries that may be replaced by a staircase surface. The corresponding electromagnetic solvers are closer to the software based on the mesh methods in generality, in the same time saving the high accuracy and computation speed typical for highly specialized mode-matching procedures.
TL;DR: In this paper, a new model (zCable) is proposed to represent the frequency-dependence of cable parameters directly in phase coordinates, thus avoiding the problems related to frequency-dependent transformation matrices.
Abstract: A major difficulty in multiphase cable modeling with traditional electromagnetic transient program like the EMTP is the synthesis of the frequency-dependent transformation matrix which relates modal and phase domain variables. This paper presents a new model (zCable) to represent the frequency-dependence of cable parameters directly in phase coordinates thus avoiding the problems related to frequency-dependent transformation matrices. The cable model is split into two parts: a constant ideal line section and a frequency-dependent loss section. A pi-correction is proposed to solve the problem of different traveling times in the ideal line section. The main advantage of the proposed model as compared to existing frequency-dependent transformation matrix models is the model's absolute numerical stability for strongly asymmetrical cable configurations and for arbitrary fault conditions. In addition, the model parameters are easy to obtain with robust algorithms and the model can be efficiently implemented in the context of a real-time PC-cluster simulator.
10 Nov 2002
TL;DR: This paper describes a procedure to generate numerically a set of basis functions which efficiently represent conductor current variation, and thus improving solver efficiency, based on solving a sequence of template problems.
Abstract: Modeling the exponentially varying current distributions in conductor interiors associated with high frequency interconnect behavior causes a rapid increase in the computation time and memory required even by recently developed fast electromagnetic analysis programs. In this paper we describe a procedure to generate numerically a set of basis functions which efficiently represent conductor current variation, and thus improving solver efficiency. The method is based on solving a sequence of template problems, and is easily generalized to arbitrary conductor cross-sections. Results are presented to demonstrate that the numerically computed basis functions are seven to twenty times more efficient than the commonly used piece-wise constant basis functions.
02 Jun 2002
TL;DR: In this article, the electromagnetic isolation and coupling characteristics of basic structures, namely metal pads, spiral inductors, and spiral transistors, implemented in a core-logic CMOS process are evaluated and modeled.
Abstract: The electromagnetic isolation and coupling characteristics of basic structures, namely metal pads, spiral inductors, and spiral-transistors, implemented in a core-logic CMOS process are evaluated and modeled. The models provide design guidelines on the isolation characteristics of guard-rings and shield layers for RF cross-talk suppression between circuit blocks. The importance of electromagnetic coupling to layout interconnects is demonstrated.
TL;DR: A simple algorithm to expedite the generation of finite-different time-domain grids with specific spatial resolution is discussed, along with sample results.
Abstract: The finite-different time-domain (FDTD) method has become a popular method in computational electromagnetics because of its simplicity, flexibility, and efficiency. However, the process of generating a three-dimensional (3D) FDTD grid can be time-consuming and error-prone when manually manipulating complex geometries. In order to expedite the generation of FDTD grids, computer-graphics-based methods can alternatively be used. Starting from the geometric description of the problem domain given by a CAD file, an FDTD grid with a specific spatial resolution can be automatically produced. A simple algorithm to this end is discussed, along with sample results.