Showing papers on "Computational electromagnetics published in 2004"
TL;DR: A new hierarchical basis of arbitrary order for integral equations solved with the method of moments derived from orthogonal Legendre polynomials which are modified to impose continuity of vector quantities between neighboring elements while maintaining most of their desirable features is presented.
Abstract: This paper presents a new hierarchical basis of arbitrary order for integral equations solved with the method of moments (MoM). The basis is derived from orthogonal Legendre polynomials which are modified to impose continuity of vector quantities between neighboring elements while maintaining most of their desirable features. Expressions are presented for wire, surface, and volume elements but emphasis is given to the surface elements. In this case, the new hierarchical basis leads to a near-orthogonal expansion of the unknown surface current and implicitly an orthogonal expansion of the surface charge. In addition, all higher order terms in the expansion have two vanishing moments. In contrast to existing formulations, these properties allow the use of very high-order basis functions without introducing ill-conditioning of the resulting MoM matrix. Numerical results confirm that the condition number of the MoM matrix obtained with this new basis is much lower than existing higher order interpolatory and hierarchical basis functions. As a consequence of the excellent condition numbers, we demonstrate that even very high-order MoM systems, e.g., tenth order, can be solved efficiently with an iterative solver in relatively few iterations.
247 citations
TL;DR: In this paper, a series of hierarchical implicit derivative matching methods are proposed to restore the accuracy of high-order finite-difference time-domain (FDTD) schemes of computational electromagnetics (CEM) with material interfaces in one (1D) and two spatial dimensions (2D).
215 citations
TL;DR: In this paper, the use of the Kriging models for objective function approximations and their use on electromagnetic device optimization is discussed. And the models are compared with some radial basis function neural networks and with the diffuse element method.
Abstract: This paper deals with the use of the Kriging models for objective function approximations and their use on electromagnetic device optimization. The models are compared with some radial basis function neural networks and with the diffuse element method. Comparative tests are done on an analytical function and on the TEAM workshop problem 25.
201 citations
TL;DR: In this article, a parallel finite-difference algorithm for the solution of diffusive, three-dimensional transient electromagnetic field simulations is presented using a staggered grid and a modified DuFort-Frankel method, the scheme steps Maxwell's equations in time.
Abstract: A parallel finite-difference algorithm for the solution of diffusive, three-dimensional (3D) transient electromagnetic field simulations is presented. The purpose of the scheme is the simulation of both electric fields and the time derivative of magnetic fields generated by galvanic sources (grounded wires) over arbitrarily complicated distributions of conductivity and magnetic permeability. Using a staggered grid and a modified DuFort-Frankel method, the scheme steps Maxwell's equations in time. Electric field initialization is done by a conjugate-gradient solution of a 3D Poisson problem, as is common in 3D resistivity modeling. Instead of calculating the initial magnetic field directly, its time derivative and curl are employed in order to advance the electric field in time. A divergence-free condition is enforced for both the magnetic-field time derivative and the total conduction-current density, providing accurate results at late times. In order to simulate large realistic earth models, the algorithm has been designed to run on parallel computer platforms. The upward continuation boundary condition for a stable solution in the infinitely resistive air layer involves a two-dimensional parallel fast Fourier transform. Example simulations are compared with analytical, integral-equation and spectral Lanczos decomposition solutions and demonstrate the accuracy of the scheme.
168 citations
TL;DR: In this article, the authors show that the electromagnetic field in the perfectly matched layers (PML) is bounded by a time independent constant, hence they are long-time stable, and prove that the linear growth of the electromagnetic fields in the layer is undesirable.
Abstract: This paper shows how to eliminate an undesirable long-time linear growth of the electromagnetic field in a class of unsplit perfectly matched layers (PML) typically used as absorbing boundary conditions in computational electromagnetics codes. For the new PML equations, we give energy arguments that show the fields in the layer are bounded by a time-independent constant, hence they are long-time stable. Numerical experiments confirm the elimination of the linear growth, and the long-time boundedness of the fields.
155 citations
TL;DR: This study shows that a good quality SAI preconditioner can be constructed by using the near part matrix numerically generated in the MLFMA and can reduce the number of Krylov iterations substantially.
Abstract: In computational electromagnetics, the multilevel fast multipole algorithm (MLFMA) is used to reduce the computational complexity of the matrix vector product operations. In iteratively solving the dense linear systems arising from discretized hybrid integral equations, the sparse approximate inverse (SAI) preconditioning technique is employed to accelerate the convergence rate of the Krylov iterations. We show that a good quality SAI preconditioner can be constructed by using the near part matrix numerically generated in the MLFMA. The main purpose of this study is to show that this class of the SAI preconditioners are effective with the MLFMA and can reduce the number of Krylov iterations substantially. Our experimental results indicate that the SAI preconditioned MLFMA maintains the computational complexity of the MLFMA, but converges a lot faster, thus effectively reduces the overall simulation time.
134 citations
TL;DR: Through accurate and fast EM-based neural models of passive components, this paper enables consideration of EM effects in high-frequency and high-speed computer-aided design, including component's geometrical/physical parameters as optimization variables.
Abstract: In this paper, artificial neural-network approaches to electromagnetic (EM)-based modeling in both frequency and time domains and their applications to nonlinear circuit optimization are presented. Through accurate and fast EM-based neural models of passive components, we enable consideration of EM effects in high-frequency and high-speed computer-aided design, including component's geometrical/physical parameters as optimization variables. Formulations for standard frequency-domain neural modeling approach, and recent time-domain neural modeling approach based on state-space concept, are described. A new EM-based time-domain neural modeling approach combining existing knowledge in the form of equivalent circuits (ECs), with state-space equations (SSEs) and neural networks (NNs), called the EC-SSE-NN, is proposed. The EC-SSE-NN models allow EM behaviors of passive components in the circuit to interact with nonlinear behaviors of active devices, and facilitate nonlinear circuit optimization in the time domain. An automatic mechanism for EM data generation, which can lead to efficient training of neural models for EM components, is presented. Demonstration examples including EM-based frequency-domain optimization of a three-stage amplifier, time-domain circuit optimization in a multilayer printed circuit board, including geometrical/physical-oriented neural models of power-plane effects, and EM-based optimization of a high-speed interconnect circuit with embedded passive terminations and nonlinear buffers in the time domain are presented.
114 citations
TL;DR: In this paper, the authors present an approach for directly coupling transient magnetic fields and electric circuits, which can contain arbitrarily connected solid conductors located in the magnetic field region, and a systematic procedure suitable for both nodal and loop method is used to couple fields and circuits.
Abstract: We present an approach for directly coupling transient magnetic fields and electric circuits. The circuit can contain arbitrarily connected solid conductors located in the magnetic field region. A systematic procedure suitable for both nodal method and loop method is used to couple fields and circuits. The structures of the system equations of the two methods are analogous. The formulations allow the equations in stranded windings and solid conductors to be unified and the coefficient matrix of the system equations to be symmetrical. In order to reduce the solution domain, the periodic boundary conditions are still applicable when the solid conductors are involved. Our approach has been applied to the simulation of electric machines. We give four examples: 1) calculation of the input phase current and output torque when a single-phase induction motor with shaded rings is in locked-rotor operation; 2) simulation of the sudden short circuit of a synchronous generator with starting cage; 3) study of the phase current waveform of an induction motor when the rotor bars are broken; and 4) investigation of the parasitic capacitive impact of the surge voltage on a winding due to drive switching and cable ring.
106 citations
TL;DR: Some modern trends in nonlinear (NL) microwave circuit optimization based on electromagnetic (EM) simulation are discussed, including space mapping, domain partitioning, and neural-network modeling of the passive subnetwork and/or of its most critical parts.
Abstract: This paper discusses some modern trends in nonlinear (NL) microwave circuit optimization based on electromagnetic (EM) simulation. In order to keep the CPU time required for a typical design within acceptable limits, the number of expensive EM analyses must be kept under tight control. This may be obtained by resorting to a systematic implementation of some modern algorithmic concepts such as space mapping, domain partitioning, and neural-network modeling of the passive subnetwork and/or of its most critical parts. Although these techniques are well established for linear microwave circuit design coupled with EM analysis, their extension to the NL case is not trivial, and deserves a specialized treatment. Several examples are presented in order to give a feeling of the state-of-the-art of NL/EM optimization.
97 citations
20 Apr 2004
TL;DR: This paper presents the most recent progress in the area of FPGA-based 3D FDTD accelerators, and three aspects of the design are discussed, including the host-PC interface, memory hierarchy, and computational datapath.
Abstract: In order to take advantage of the significant benefits afforded by computational electromagnetic techniques, such as the finite-difference time-domain (FDTD) method, solvers capable of analyzing realistic problems in a reasonable time frame are required. Although software-based solvers are frequently used, they are often too slow to be of practical use. To speed up computations, hardware-based implementations of the FDTD method have been recently proposed. In this paper, we present our most recent progress in the area of FPGA-based 3D FDTD accelerators. Three aspects of the design are discussed, including the host-PC interface, memory hierarchy, and computational datapath. Implementation and benchmarking results are also presented, demonstrating that this accelerator is capable of at least three-fold speedups over thirty-node PC clusters.
91 citations
TL;DR: In this article, a method for the efficient optimization of microwave filters and multiplexers designed from an ideal prototype is presented based on the estimation of a rational function adjusted to a reduced number of samples of the microwave device response obtained either through electromagnetic analysis or measurements.
Abstract: A method is presented for the efficient optimization of microwave filters and multiplexers designed from an ideal prototype. The method is based on the estimation of a rational function adjusted to a reduced number of samples of the microwave device response obtained either through electromagnetic analysis or measurements. From this rational function, a circuital network having the previously known topology of the microwave device is synthesized and compared to a circuital network with the desired response but including nonidealities. All of the process of analysis and model extraction can be seen as a model function that relates the physical parameters of the microwave device with the extracted circuital network parameters. Then, the error vector of the circuital parameters is used to generate a correction vector of the physical parameters through an estimation of the inverse of the Jacobian matrix of the complete model function. The Jacobian estimation is updated at each iteration of the optimization process with no need for additional evaluations of the model function. Two numerical examples of the proposed technique corresponding to the synthesis of a filter and a diplexer are presented, demonstrating the increased efficiency of the proposed technique with respect to direct electromagnetic optimization.
TL;DR: In this paper, a novel algorithm for efficient estimation of objective function sensitivities for time-domain transmission-line modeling (TLM) with nondispersive boundaries is presented, which is illustrated through the estimation of the sensitivities of objective functions with respect to the dimensions of waveguide discontinuities.
Abstract: We present a novel algorithm for efficient estimation of objective function sensitivities for time-domain transmission-line modeling (TLM) with nondispersive boundaries. The original electromagnetic structure is simulated using TLM. An adjoint TLM simulation that runs backward in time is derived and solved. The sensitivities of the objective function with respect to all designable parameters are estimated using only the original and adjoint simulations. Our approach is illustrated through the estimation of the sensitivities of objective functions with respect to the dimensions of waveguide discontinuities. A very good match is obtained between our sensitivity estimates and those obtained through the accurate and time-intensive central difference approximation.
TL;DR: In this article, a p-type multiplicative Schwarz (pMUS) method was proposed for solving three-dimensional waveguide discontinuity problems, which used hierarchical curl-conforming basis functions that incorporated a discrete Hodge decomposition explicitly and treated each polynomial space as an abstract grid/domain in the Schwarz method.
Abstract: This paper presents the application of a p-type multiplicative Schwarz (pMUS) method for solving three-dimensional waveguide discontinuity problems. The two major contributions of the proposed pMUS method are: 1) the use of hierarchical curl-conforming basis functions that incorporate a discrete Hodge decomposition explicitly and 2) the treatment of each polynomial space (or basis functions group) as an abstract grid/domain in the Schwarz method. These two features greatly improve the applicability of the curl-conforming vector finite-element methods (FEMs) for solving Maxwell equations. Various numerical examples are solved using the proposed approach. The performance of the pMUS method has been compared to commercial FEM software as well as the incomplete Choleski conjugate gradient method. It is found that the pMUS method exhibits superior efficiency and consumes far less memory and CPU times.
TL;DR: A new hybrid method using Kriging metamodeling in conjunction with the divided rectangles (DIRECT) global- Optimization algorithm is used to yield a globally optimal solution efficiently and inherits both local and global-optimization properties.
Abstract: With the advent of fast methods to significantly speed up numerical computation of large-scale realistic electromagnetic (EM) structures, EM design and optimization is becoming increasingly attractive. In recent years, genetic algorithms, neural network and evolutionary optimization methods have become increasingly popular for EM optimization. However, these methods are usually associated with a slow convergence bound and, furthermore, may not yield a deterministic optimal solution. In this paper, a new hybrid method using Kriging metamodeling in conjunction with the divided rectangles (DIRECT) global-optimization algorithm is used to yield a globally optimal solution efficiently. The latter yields a deterministic answer with fast convergence bounds and inherits both local and global-optimization properties. Three examples are given to illustrate the applicability of the method, Le., shape optimization for a slot-array frequency-selective surface, antenna location optimization to minimize EM coupling from the antenna to RF devices in automobile structures, and multisensor optimization to satisfy RF coupling constraints on a vehicular chassis in the presence of a wire harness. In the first example, DIRECT with Kriging surrogate modeling was employed. In the latter two examples, the adaptive hybrid optimizer, superEGO, was used. In all three examples, emphasis is placed on the speed of convergence, as well as on the flexibility of the optimization algorithms.
TL;DR: An efficient rational function fitting methodology, called VECTFIT, is utilized toward the closed-form evaluation of the Sommerfeld integrals associated with electromagnetic Green's functions in planar layered media as mentioned in this paper.
Abstract: An efficient rational function fitting methodology, called VECTFIT, is utilized toward the closed-form evaluation of the Sommerfeld integrals associated with electromagnetic Green's functions in planar layered media. VECTFIT approximates the component of the spectrum of the Green's function that remains after the extraction of the primary source contribution and the quasistatic part with a rational function, thus enabling a robust and expedient closed-form evaluation of the Sommerfeld integral for electromagnetic potentials and associated field quantities.
TL;DR: This paper presents an adaptation of the scheme to the analysis of electromagnetic problems in both the static and quasi-static regimes and validates the proposed model against both analytical solutions and benchmarked FEMs.
Abstract: Conventional finite-element methods (FEMs) rely on an underlying tessellation to describe the geometry and the basis functions that are used to represent the unknown quantity. Alternatively, however, it is possible to represent both the geometry and basis as a set of points. This alternative scheme has been used extensively in solid mechanics to compute stress and strain distributions. This paper presents an adaptation of the scheme to the analysis of electromagnetic problems in both the static and quasi-static regimes. It validates the proposed model against both analytical solutions and benchmarked FEMs. The paper demonstrates the efficacy of the proposed method by applying it to a range of problems.
TL;DR: In this article, a plane-wave-time-domain accelerated time-domain integral-equation solver is coupled to a SPICE-like transient circuit simulator to analyze electromagnetic platform-circuit interactions.
Abstract: A plane-wave-time-domain accelerated time-domain integral-equation solver is coupled to a SPICE-like transient circuit simulator to analyze electromagnetic platform-circuit interactions. The hybrid field-circuit simulator simultaneously solves surface-wire-volume time-domain integral equations that model electromagnetic interactions with the platform and modified nodal analysis equations that govern the behavior of the potentially nonlinear lumped circuits. A shielded nonlinear microwave amplifier is analyzed using the proposed scheme, and its immunity to electromagnetic interference is assessed.
TL;DR: This work reviews fundamental concepts such as types of error measures, properties of the problem and numerical method that affect error, the optimality principle, and basic approximation error estimates.
Abstract: Because of the widespread use of the Method of Moments for simulation of radiation and scattering problems, analysis and control of solution error is a significant concern in computational electromagnetics. The physical problem to be solved, its mesh representation, and the numerical method all impact accuracy. Although empirical approaches such as benchmarking are used almost exclusively in practice for code validation and accuracy assessment, a number of significant theoretical results have been obtained in recent years, including proofs of convergence and solution-error estimates. This work reviews fundamental concepts such as types of error measures, properties of the problem and numerical method that affect error, the optimality principle, and basic approximation error estimates. Analyses are given for surface-current and scattering-amplitude errors for several scatterers, including the effects of edge and corner singularities and quadrature error. We also review results on ill-conditioning due to resonance effects and the convergence rates of iterative linear-system solutions.
TL;DR: An accurate uniform theory of diffraction model for the analysis of complex indoor radio environments, in which microwave WLAN systems operate, is presented and results show that the electromagnetic field distribution and the channel performances are significantly influenced by the diffraction processes arising from the presence of furniture.
Abstract: An accurate uniform theory of diffraction (UTD) model for the analysis of complex indoor radio environments, in which microwave WLAN systems operate, is presented. The model employs a heuristic UTD coefficient suitable to take into account the effects of building floors, walls, windows, and the presence of metallic and penetrable furniture. A numerical tool based on an enhanced tridimensional beam-tracing algorithm, which includes diffraction phenomena, has been developed to compute the field distribution with a high degree of accuracy. After the validation of the model, obtained by means of some comparisons with measurements available in literature, an accurate electromagnetic characterization of typical indoor environments has been performed. The numerical results show that the electromagnetic field distribution and the channel performances are significantly influenced by the diffraction processes arising from the presence of furniture.
06 Jun 2004
TL;DR: In this paper, a multiplane precorrected fast Fourier transform (PFFT) computational engine is implemented on a set of two-dimensional fast-fraction transform grids associated with the current sheets corresponding to the conductor loss models.
Abstract: A methodology for efficient parasitic extraction and verification flow for RF and mixed-signal integrated-circuit designs is presented. The implementation of a multiplane precorrected fast Fourier transform (PFFT) computational engine enables the full-wave electromagnetic (EM) simulation of interconnects and passive components. The PFFT algorithm is implemented on a set of two-dimensional fast Fourier transform grids associated with the current sheets corresponding to the conductor loss models. This leads to the full-wave modeling of silicon embedded three-dimensional circuits within the two-and-one-half-dimensional computational framework yielding the O(NlogN) computational complexity and O(N) memory requirements of the algorithm. The broad-band capability of the EM solver is provided through the loop-tree/charge implementation of the PFFT algorithm allowing for robust full-wave modeling from dc to microwaves. The EM verification flow is integrated seamlessly within the Cadence environment allowing for the nonlinear circuit simulation of the entire device. The capability and accuracy of the proposed methodology is demonstrated through EM simulation results for an individual on-chip spiral inductor, as well as a low-noise amplifier.
TL;DR: An analysis of the global design and modeling process with a reluctance network that defines the relative place of the designer versus methodologies and tools is proposed.
Abstract: Models of electromagnetic devices using reluctance networks are very interesting, especially for sizing and optimization. Unfortunately, too often, designers do not use them because they are time consuming to implement, mainly for complicated aspects like the need to write and solve the network equations. We have developed a tool that automates all those symbolic and numeric tasks. We also generate software components that allow to use those models very efficiently in an optimization process by providing the formal right sensitivity. We present the methodology and software, as well as their application on examples. This paper proposes also an analysis of the global design and modeling process with a reluctance network that defines the relative place of the designer versus methodologies and tools.
TL;DR: The objectives of this paper are to identify some of challenging problems encountered by the author during the last five years, and to present the results of application of a technique called CBFM - developed at the EMC Laboratory at Penn State - that has been found useful for addressing them.
Abstract: Recent years have seen a spectacular increase in our capability to model, simulate the performance of, and design complex electromagnetic systems. Much progress has been made in enhancing the available numerical techniques, viz., the method of moments (MoM), the finite-element method (FEM), and the finite-difference time-domain (FDTD) or its variants. Great strides have recently been made in enlarging the scope of MoM via the use of the fast multipole method (FMM), which has made it feasible for us to solve problems that require the handling of 106 degrees of freedom, or even higher, and distributed processing has enabled the FDTD to handle upward of 109 degrees of freedom on a moderate-size computing platform. Despite this recent progress, many practical computational electromagnetic (CEM) modeling problems of interest present formidable challenges, and the search for numerically efficient techniques to solve large problems involving complex structures continues unabated. The objectives of this paper are to identify some of these challenging problems encountered by the author during the last five years, and to present the results of application of a technique called CBFM - developed at the EMC Laboratory at Penn State - that has been found useful for addressing them.
TL;DR: In this paper, a comprehensive simulation of ultra-wideband signal propagation in indoor environments is presented, based on time domain electromagnetic modeling of transmitting and receiving antennas and the analysis of wave propagation through indoor channels using the time-domain uniform theory of diffraction.
Abstract: A comprehensive simulation of ultra-wideband signal propagation in indoor environments is presented. The simulation is based on time-domain electromagnetic modeling of transmitting and receiving antennas and the analysis of wave propagation through indoor channels using the time-domain uniform theory of diffraction. The antennas are a pair of TEM horns which are modeled as arrays of vee dipoles. The analysis of these antennas is performed directly in the time domain, without the need for transforming the solutions from the frequency domain to the time domain. The frequency dependence of materials utilized in the structure on the indoor channel is accounted for in the channel simulation. The simulation results are compared with the corresponding measured results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 103–108, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20221
TL;DR: In this article, the authors presented a novel algorithm for efficient estimation of objective function sensitivities for time-domain transmission-line modeling (TLM) with dispersive Johns matrix boundaries.
Abstract: We present a novel algorithm for efficient estimation of objective function sensitivities for time-domain transmission-line modeling (TLM) with dispersive Johns matrix boundaries. The original electromagnetic structure is simulated using TLM. An adjoint TLM simulation that runs backward in time is derived and solved. The sensitivities of the objective function with respect to all designable parameters are estimated using only the original and adjoint simulations. We show that the Johns matrix of the adjoint problem at each time step is the transpose of the corresponding matrix for the original structure. Our approach is illustrated through the estimation of the sensitivities of objective functions with respect to the dimensions of waveguide discontinuities. A very good match is obtained between our sensitivity estimates and those obtained using central difference approximation.
TL;DR: In this article, a general framework is presented, within which stationary FE-BI formulations can be established (variational boundary value problems), which relate to equivalent, underlying variational principles (stationary functionals).
Abstract: This paper addresses the time-harmonic, electromagnetic analysis of a three-dimensional inhomogeneous radiator/scatterer in free-space. Such analysis can be carried out by combining the finite element method (FEM) with the method of moments (MoM), which yields finite element-boundary integral (FE-BI) formulations. A general framework is presented, within which stationary FE-BI formulations can be established (variational boundary-value problems), which relate to equivalent, underlying variational principles (stationary functionals). The formulations are shown to be accurate, robust and computationally efficient. They avoid the problem of interior resonances without resorting to the combined field integral equation and they result in symmetric system matrices, which preserve reciprocity explicitly. Thus, the stationary FE-BI framework combines the FEM and MoM on the continuous level, as opposed to the usual approach of hybridization after discretization, which generally leads to asymmetric matrices. The stationary FE-BI framework allows one to solve either for the electric and magnetic fields on the volume of the problem domain, or for one volume and one exterior surface field quantity, with only marginal differences in computational cost. The volume-surface formulations have the same storage requirements as previous FE-BI formulations and can be more efficiently solved. The volume-volume formulations provide simultaneous solutions of the electric and magnetic fields, which could for instance be used to construct error estimators directly based on Maxwell's equations.
TL;DR: The significant advances in computer modeling of electromagnetic interactions that have taken place over the last two decades have made it possible to shift the classical “trial and error” design paradigm for electromagnetic devices to one that is more flexible and scalable.
Abstract: Electromagnetic devices are ubiquitous in present day technology. Indeed, electromagnetism has found and continues to find applications in a wide array of areas, encompassing both civilian and military purposes. Among the former, applications of current interest include those related to communications (e.g. transmission through optical fiber lines), to biomedical devices and health (e.g. tomography, power-line safety, etc), to circuit or magnetic storage design (electromagnetic compatibility — EMC—, hard disc operation), to geophysical prospecting, and to non-destructive evaluation (e.g. crack detection), to name but just a few. Equally notable and motivating are applications in defense which include the design of military hardware with decreased signatures (“virtual prototyping”); automatic target recognition — ATR— (e.g. bunkers, mines and buried ordnance, etc); propagation effects on communications and radar systems (e.g. over complex terrains); tactical antenna design; etc. Although the principles of electromagnetics are well understood (see §2), their application to practical configurations of current interest, such as those that arise in connection with the examples above, is significantly complicated and far beyond manual calculation in all but the simplest aspects. These complications typically arise from geometrical and/or compositional complexity in the underlying structures (e.g. circuits, military hardware, biological tissue), from the intricacies of the electromagnetic fields (especially at higher frequencies), or from both. The significant advances in computer modeling of electromagnetic interactions that have taken place over the last two decades, on the other hand, have made it possible to shift the classical “trial and error” design paradigm for electromagnetic devices to one that
23 May 2004
TL;DR: Off-the-shelf graphics processor units (GPUs) can be successfully used to accelerate FDTD simulations and it is demonstrated that the GPU outperforms a central processing unit (CPU) of comparable technology generation.
Abstract: The finite-difference time-domain (FDTD) algorithm has become a tool of choice in many areas of RF and microwave engineering and optics. However, FDTD runs too slow for some simulations to be practical, even when carried out on supercomputers. The development of dedicated hardware to accelerate FDTD computations has been investigated. In this paper, we demonstrate that off-the-shelf graphics processor units (GPUs) can be successfully used to accelerate FDTD simulations. Using C++, OpenGL, and several OpenGL extensions, a modern GPU has been programmed to solve a simple two dimensional electromagnetic scattering problem. The GPU outperforms a central processing unit (CPU) of comparable technology generation.
TL;DR: In this article, the dispersion errors of higher order finite-difference time domain (HO-FDTD) algorithms are compared to those of multiresolution time-domain (MRTD) algorithm that have equivalent spatial stencil sizes.
Abstract: The dispersion errors of higher order finite-difference time-domain (HO-FDTD) algorithms are compared to those of multiresolution time-domain (MRTD) algorithms that have equivalent spatial stencil sizes. Both scaling-function-based MRTD (S-MRTD) and wavelet-function-based MRTD (W-MRTD) schemes are considered. In particular, the MRTD schemes considered include the Coifman scaling functions and the Cohen-Daubechies-Feauveau (CDF) biorthogonal scaling and wavelet functions. In general, the HO-FDTD schemes are more accurate than their MRTD counterparts.
TL;DR: In this paper, the unconditionally stable alternating-direction-implicit-finite-difference time-domain (ADI-FDTD) method is used to model wave propagation in dispersive media.
Abstract: The unconditionally stable alternating-direction-implicit-finite-difference time-domain (ADI-FDTD) method is used to model wave propagation in dispersive media. A formulation is presented by introducing the Z-transform method into the ADI-FDTD scheme to handle the frequency-dependent features of the media. This formulation is applicable to arbitrary dispersive media, and can be easily coded. Numerical results are compared to those based on the conventional FDTD method to show the efficiency of the proposed method.