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Proceedings of the IEEE

Issue 2 • Date Feb. 2013

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Displaying Results 1 - 25 of 34
  • Front cover

    Page(s): C1
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  • Proceedings of the IEEE publication information

    Page(s): C2
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  • Table of contents

    Page(s): 217 - 219
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  • The motivation and technique of writing scientific contributions [Point of View]

    Page(s): 220 - 222
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  • Large-Scale Electromagnetic Computation for Modeling and Applications [Scanning the Issue]

    Page(s): 223 - 226
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  • Overview of Large-Scale Computing: The Past, the Present, and the Future

    Page(s): 227 - 241
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (999 KB) |  | HTML iconHTML  

    This is a brief review of the development of computational electromagnetics (CEM) to partially summarize its achievements, issues, and possibilities. View full abstract»

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  • Discontinuous Galerkin Time-Domain Methods for Multiscale Electromagnetic Simulations: A Review

    Page(s): 242 - 254
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (988 KB) |  | HTML iconHTML  

    Efficient multiscale electromagnetic simulations require several major challenges that need to be addressed, such as flexible and robust geometric modeling schemes, efficient and stable time-stepping methods, etc. Due to the versatile choices of spatial discretization and temporal integration, discontinuous Galerkin time-domain (DGTD) methods can be very promising in simulating transient multiscale problems. This paper provides a comprehensive review of different DGTD schemes, highlighting the fundamental issues arising in each step of constructing a DGTD system. The issues discussed include the selection of governing equations for transient electromagnetic analysis, different basis functions for spatial discretization, as well as the implementation of different time-stepping schemes. Numerical examples demonstrate the advantages of DGTD for multiscale electromagnetic simulations. View full abstract»

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  • Electromagnetic Computation in Scattering of Electromagnetic Waves by Random Rough Surface and Dense Media in Microwave Remote Sensing of Land Surfaces

    Page(s): 255 - 279
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4301 KB) |  | HTML iconHTML  

    Active and passive microwave remote sensing has been used for monitoring the soil moisture and snow water equivalent. In the interactions of microwaves with bare soil, the effects are determined by scattering of electromagnetic waves by random rough surfaces. In the interactions of microwaves with terrestrial snow, the effects are determined by volume scattering of dense media characterized by densely packed particles. In this paper, we review the electromagnetic full-wave simulations that we have conducted for such problems. In volume scattering problems, one needs many densely packed scatterers in a random medium sample to simulate the physical solutions. In random rough surface scattering problems, one needs many valleys and peaks in the sample surface. In random media and rough surface problems, the geometric characterizations of the media and computer generations of statistical samples of the media are also challenges besides electromagnetic computations. In the scattering of waves by soil surfaces, we consider the soil to be a lossy dielectric medium. The random rough surface is characterized by Gaussian random processes with exponential correlation functions. Surfaces of exponential correlation functions have fine-scale structures that cause significant radar backscattering in active microwave remote sensing. Fine-scale features also cause increase in emission in passive microwave remote sensing. We apply Monte Carlo simulations of solving full 3-D Maxwell's equations for such a problem. A hybrid UV/PBTG/SMCG method is developed to accelerate method of moment solutions. The results are illustrated for coherent waves and incoherent waves. We also illustrate bistatic scattering, backscattering, and emissivity which are signatures measured in microwave remote sensing. For the case of scattering by terrestrial snow, snow is a dense medium with densely packed ice grains. We have used two models: densely packed particles and bicontinuous media. For the case of de- sely packed particles, we used the Metropolis shuffling method to simulate the positions of particles. The particles are also allowed to have adhesive properties. The Foldy-Lax equations of multiple scattering are used to study scattering from the densely packed spherical particles. The results are illustrated for the coherent waves and incoherent waves. For the case of bicontinuous media, the method developed by Cahn is applied to construct the interfaces from a large number of stochastic sinusoidal waves with random phases and directions. The volume scattering problem is then solved by using CGS-FFT. We illustrate the results of frequency and polarization dependence of such dense media scattering. View full abstract»

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  • Integration of Antennas Onboard Vehicles and Diffraction by Large and Complex Structures With Multiple-Domain–Multiple-Methods Techniques

    Page(s): 280 - 297
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2755 KB) |  | HTML iconHTML  

    In this paper, we present a review of recent developments achieved in a multiple-domain-multiple-method calculation methodology in the frequency domain for the prediction of airborne antenna radiation and the diffraction of large targets. Furthermore, special attention is paid both to proposing a consistent and collaborative calculation procedure that ensures that industrial confidentiality is protected and also to guaranteeing large gains in accuracy and computing time in the parametric study phase on large objects (search for an optimal installation of the radiating parts, optimization of the antenna design mounted on the vehicle, radar cross-section modulation induced by fan rotations, etc.). View full abstract»

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  • Nonconformal Domain Decomposition Methods for Solving Large Multiscale Electromagnetic Scattering Problems

    Page(s): 298 - 319
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2842 KB) |  | HTML iconHTML  

    In this paper, we present our efforts in combating a challenging large multiscale electromagnetic scattering problem, viz. a plane-wave scattering from a mockup partially coated composite jet aircraft at X-band. We first summarize the application of the newly developed integral equation domain decomposition method (IE-DDM) to compute the plane-wave scattering from the jet aircraft, however with neither dielectrics nor lossy thin coatings. We proceed to compute the scattering from the aircraft with dielectrics and lossy thin coatings by employing two additional computational electromagnetics (CEM) techniques: a generalized combined field integral equation (G-CFIE) method to calculate electromagnetics (EM) scatterings from penetrable dielectric targets, and a hybrid finite elements and boundary elements method tailored specifically to address perfect electric conductor (PEC) targets partially coated with lossy thin materials. View full abstract»

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  • Hybrid Iterative Approach Combined With Domain Decomposition for the Analysis of Large Electromagnetic Problems

    Page(s): 320 - 331
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1005 KB) |  | HTML iconHTML  

    In this paper, we propose a technique for the electromagnetic analysis of large objects considering the interactions between separate parts of the geometry (which in this context will be referred to as domains). A number of unknowns is associated to each domain, and only the basis functions included within the same domain are considered fully coupled (i.e., a full-wave analysis is performed for every domain, isolating it from the rest of the geometry). An iterative process is then applied to determine the total currents over the object, considering the currents induced by the external sources and those due to interactions between different domains. Once a current distribution is obtained over a given domain it is essential to identify those passive domains with which the interaction active-domain-passive-domain will yield a significant contribution to the final result (scattered field, radiation pattern, S-parameters, etc.). In this work, we utilize a ray-tracing method combined with the multipole expansion of the active currents over a number of points located on the radiating surface to speed up the solution of large and realistic problems. View full abstract»

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  • Hierarchical parallelization of the multilevel fast multipole algorithm (MLFMA)

    Page(s): 332 - 341
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2102 KB) |  | HTML iconHTML  

    Due to its O(N log N) complexity, the multilevel fast multipole algorithm (MLFMA) is one of the most prized algorithms of computational electromagnetics and certain other disciplines. Various implementations of this algorithm have been used for rigorous solutions of large-scale scattering, radiation, and miscellaneous other electromagnetics problems involving 3-D objects with arbitrary geometries. Parallelization of MLFMA is crucial for solving real-life problems discretized with hundreds of millions of unknowns. This paper presents the hierarchical partitioning strategy, which provides a very efficient parallelization of MLFMA on distributed-memory architectures. We discuss the advantages of the hierarchical strategy over previous approaches and demonstrate the improved efficiency on scattering problems discretized with millions of unknowns. View full abstract»

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  • Accurate solutions of extremely large integral-equation problems in computational electromagnetics

    Page(s): 342 - 349
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1120 KB) |  | HTML iconHTML  

    Accurate simulations of real-life electromagnetics problems with integral equations require the solution of dense matrix equations involving millions of unknowns. Solutions of these extremely large problems cannot be achieved easily, even when using the most powerful computers with state-of-the-art technology. However, with the multilevel fast multipole algorithm (MLFMA) and parallel MLFMA, we have been able to obtain full-wave solutions of scattering problems discretized with hundreds of millions of unknowns. Some of the complicated real-life problems (such as scattering from a realistic aircraft) involve geometries that are larger than 1000 wavelengths. Accurate solutions of such problems can be used as benchmarking data for many purposes and even as reference data for high-frequency techniques. Solutions of extremely large canonical benchmark problems involving sphere and National Aeronautics and Space Administration (NASA) Almond geometries are presented, in addition to the solution of complicated objects, such as the Flamme. The parallel implementation is also extended to solve very large dielectric problems, such as dielectric lenses and photonic crystals. View full abstract»

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  • MLFMA-FFT Parallel Algorithm for the Solution of Extremely Large Problems in Electromagnetics

    Page(s): 350 - 363
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2100 KB) |  | HTML iconHTML  

    An efficient parallel implementation of the multilevel fast multipole algorithm-fast Fourier transform (MLFMA-FFT) has been successfully used to solve an electromagnetic problem involving one billion of unknowns, which indeed becomes the largest problem solved with the surface integral-equation approach up to now. In this paper, we present a deep review of this challenging execution, focusing on the details of the parallel implementation step by step, with the aim of describing the different stages of the parallel algorithm and analyzing its overall parallel performance. View full abstract»

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  • Accelerated Direct Solution of the Method-of-Moments Linear System

    Page(s): 364 - 371
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (574 KB) |  | HTML iconHTML  

    This paper addresses the direct (noniterative) solution of the method-of-moments (MoM) linear system, accelerated through block-wise compression of the MoM impedance matrix. Efficient matrix block compression is achieved using the adaptive cross-approximation (ACA) algorithm and the truncated singular value decomposition (SVD) postcompression. Subsequently, a matrix decomposition is applied that preserves the compression and allows for fast solution by backsubstitution. Although not as fast as some iterative methods for very large problems, accelerated direct solution has several desirable features, including: few problem-dependent parameters; fixed time solution avoiding convergence problems; and high efficiency for multiple excitation problems [e.g., monostatic radar cross section (RCS)]. Emphasis in this paper is on the multiscale compressed block decomposition (MS-CBD) algorithm, introduced by Heldring , which is numerically compared to alternative fast direct methods. A new concise proof is given for the N2 computational complexity of the MS-CBD. Some numerical results are presented, in particular, a monostatic RCS computation involving 1 043 577 unknowns and 1000 incident field directions, and an application of the MS-CBD to the volume integral equation (VIE) for inhomogeneous dielectrics. View full abstract»

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  • Direct Matrix Solution of Linear Complexity for Surface Integral-Equation-Based Impedance Extraction of Complicated 3-D Structures

    Page(s): 372 - 388
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (826 KB) |  | HTML iconHTML  

    We develop a linear-complexity direct matrix solution for the surface integral equation (IE)-based impedance extraction of arbitrarily shaped 3-D nonideal conductors embedded in a dielectric material. A direct inverse of a highly irregular system matrix composed of both dense and sparse matrix blocks is obtained in O(N) complexity with N being the matrix size. It outperforms state-of-the-art impedance solvers, be they direct solvers or iterative solvers, with fast central processing unit (CPU) time, modest memory consumption, and without sacrificing accuracy, for both small and large number of unknowns. The inverse of a 2.68-million-unknown matrix arising from the extraction of a large-scale 3-D interconnect having 128 buses, which is a matrix solution for 2.68 million right-hand sides, was obtained in less than 1.5 GB memory and 1.3 h on a single CPU running at 3 GHz. View full abstract»

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  • Quasi-Block-Cholesky Factorization With Dynamic Matrix Compression for Fast Integral-Equation Simulations of Large-Scale Human Body Models

    Page(s): 389 - 400
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1517 KB) |  | HTML iconHTML  

    In this paper, a fast direct integral-equation method for simulating human models is presented. Based on the mixed symmetric and skew-symmetric pattern of the impedance matrix, a quasi-block-Cholesky (QBC) algorithm was proposed to reduce both the memory and central processing unit (CPU) time for matrix factorization by half. Dynamic matrix compression via single-level adaptive cross approximation (ACA) was further applied to reduce the computational costs. Validity of the QBC method is provided. Numerical examples further demonstrate the practicality of the proposed method. View full abstract»

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  • Modified Phase-Extracted Basis Functions for Efficient Analysis of Scattering From Electrically Large Targets

    Page(s): 401 - 413
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1839 KB) |  | HTML iconHTML  

    In this paper, phase-extracted (MPE) basis functions with both the traveling wave terms and the standing wave terms have been proposed to analyze the scattering from the electrically large targets. This kind of basis functions, called modified phase-extracted (MPE) basis function, can be defined on the relatively large patches and constructed with the higher order hierarchical vector basis functions. The constructing idea of the MPE basis function is first introduced. Then, their characteristics were compared with the relevant basis functions. It has been demonstrated that the MPE basis function is suitable for the scattering analysis of the perfect electric conductors (PECs) with smooth convex surfaces as well as the concave structures, such as the electrically large cavities. The numerical solutions to the electromagnetic scattering from both the convex targets and the cavity-like targets with strong mutual couplings have been given to show the capability of the MPE basis functions in the description of the complex distribution of the induced current on the PEC surfaces. Some numerical examples have been given to demonstrate the validation of this kind of basis functions. View full abstract»

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  • Analyzing Large-Scale Arrays Using Tangential Equivalence Principle Algorithm With Characteristic Basis Functions

    Page(s): 414 - 422
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (700 KB) |  | HTML iconHTML  

    In this paper, the tangential equivalence principle algorithm (T-EPA) combined with characteristic basis functions (CBFs) is presented to analyze the electromagnetic scattering of large-scale antenna arrays. The T-EPA is a kind of domain decomposition scheme for the electromagnetic scattering and radiation problems based on integral equation (IE). CBFs are macrobasis functions which are constructed by conventional local basis functions. By utilizing CBFs together with the T-EPA, the scattering analysis of large-scale arrays will be much more efficient with decreased unknowns compared with the original T-EPA. Further, the multilevel fast multipole algorithm (MLFMA) is applied to accelerate the matrix-vector multiplication in the T-EPA. Numerical results are shown to demonstrate the accuracy and efficiency of the proposed technique. View full abstract»

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  • Hierarchical Matrix Preconditioning for Low-Frequency–Full-Maxwell Simulations

    Page(s): 423 - 433
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    In this paper, we propose to use hierarchical matrices as fast and robust preconditioners for a recent formulation of Maxwell's equations. This formulation was introduced by Hiptmair (IEEE Trans. Magn., vol. 44, no. 6, pp. 682-685, Jun. 2008) and remains stable in the stationary limit for nonconductive domains. The preconditioner is constructed based on a decoupling of the magnetic and electric potential. Numerical results are presented for real-life geometries and both sequential and parallel implementations. View full abstract»

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  • Electromagnetic Field Theory in (N+1) -Space-Time: A Modern Time-Domain Tensor/Array Introduction

    Page(s): 434 - 450
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    In this paper, a modern time-domain introduction is presented for electromagnetic field theory in (N+1)-space-time. It uses a consistent tensor/array notation that accommodates the description of electromagnetic phenomena in N-dimensional space (plus time), a requirement that turns up in present-day theoretical cosmology, where a unified theory of electromagnetic and gravitational phenomena is aimed at. The standard vectorial approach, adequate for describing electromagnetic phenomena in (3+1)-space-time, turns out to be not generalizable to (N+1)-space-time for N >; 3 and the tensor/array approach that, in fact, has been introduced in Einstein's theory of relativity, proves, together with its accompanying notation, to furnish the appropriate tools. Furthermore, such an approach turns out to lead to considerable simplifications, such as the complete superfluousness of standard vector calculus and the standard condition on the right-handedness of the reference frames employed. Since the field equations do no more than interrelate (in a particular manner) changes of the field quantities in time to their changes in space, only elementary properties of (spatial and temporal) derivatives are needed to formulate the theory. The tensor/array notation furthermore furnishes indications about the structure of the field equations in any of the space-time discretization procedures for time-domain field computation. After discussing the field equations, the field/source compatibility relations and the constitutive relations, the field radiated by sources in an unbounded, homogeneous, isotropic, lossless medium is determined. All components of the radiated field are shown to be expressible as elementary operations acting on the scalar Green's function of the scalar wave equation in (N+1) -space-time. Time-convolution and time-correlation reciprocity relations conclude the general theory. Finally, two items on field computation are touched- upon: the space-time-integrated field equations method of computation and the time-domain Cartesian coordinate stretching method for constructing perfectly matched computational embeddings. The performance of these items is illustrated in a demonstrator showing the 1-D pulsed electric-current and magnetic-current sources excited wave propagation in a layered medium. View full abstract»

    Open Access
  • Skin-Effect Loss Models for Time- and Frequency-Domain PEEC Solver

    Page(s): 451 - 472
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB) |  | HTML iconHTML  

    A challenging and interesting issue for the solution of large electromagnetic problems is the efficient, sufficiently accurate modeling of the broadband skin-effect loss for conducting planes and 3-D shapes. The inclusion of such models in an electromagnetic (EM) solver can be very costly in compute time and memory requirements. These issues are particularly important for the class of signal, power, and noise integrity (NI) problems. In this paper, we concentrate on partial element equivalent circuit (PEEC)-type methods which are suitable for the solution of this class of problems. Progress has been made recently in the design of skin-effect models. The difficult issues are broadband frequency-domain or time-domain problems. These models are considered in this paper. We present several solution methods, and we compare results obtained with these approaches. View full abstract»

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  • Spectral Methods and Domain Decomposition for Nanophotonic Applications

    Page(s): 473 - 483
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (936 KB) |  | HTML iconHTML  

    Nanophotonic applications often involve large-scale problems with excessive demand on computational resources. We develop a domain decomposition method (DDM) to reduce computer memory and central processing unit (CPU) time requirements by combining the spectral element method (SEM) and the spectral integral method (SIM) for large-scale finite periodic structures. The interior scattering subdomains within each period are modeled by the SEM while the exterior scattering problem is modeled by the SIM. The interactions between neighboring subdomains are modeled by the frequency-domain version of the Riemann solver. Numerical convergence of the Riemann solver is fast and weakly dependent on the size of the system. Two sets of examples demonstrate the typical nanophotonic applications: The first periodic system is a vertical coupling waveguide based on a photonic crystal slab which opens a way to construct and simulate optical circuits. The second periodic system is a finite-sized metamaterial with an effective negative refractive index, whose edge effects are visualized and analyzed. View full abstract»

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  • Highly Tailored Computational Electromagnetics Methods for Nanophotonic Design and Discovery

    Page(s): 484 - 493
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (847 KB) |  | HTML iconHTML  

    The use of computational electromagnetics (CEM) techniques has greatly advanced nanophotonics. The applications of nanophotonics in turn motivates the development of efficient highly tailored algorithms for specific application domains. In this paper, we will discuss some specific considerations in seeking to advance CEM for nanophotonic design and discovery, with examples drawn from the design of aperiodic nanophotonic structures for on-chip information processing applications. View full abstract»

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  • Water Bridges in Electropermeabilized Phospholipid Bilayers

    Page(s): 494 - 504
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1243 KB) |  | HTML iconHTML  

    Pulsed electric field permeabilization of living cell membranes forms the basis for widely used biotechnology protocols and an increasing number of therapeutic applications. Experimental observations of artificial membranes and whole cells and molecular and analytical models provide evidence that a membrane-spanning, hydrophilic, conductive pore can form in nanoseconds. An external electric field lowers the energy barrier for this stochastic process, reducing the mean time for pore formation and increasing the pore areal density. Molecular dynamic simulations reveal the key role played by interfacial water in electropermeabilization. These model systems, validated in the laboratory, are deepening our understanding of the factors governing pore initiation, construction, and lifetime, knowledge that will translate to enhanced utilization of this method in biomedicine and bioengineering. View full abstract»

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H. Joel Trussell
North Carolina State University