ACES Publication Search
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| Title: | ACES February 2012 Full Journal |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 1087 KB |
| Title: | ACES February 2012 Front/Back Matter |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 11005 KB |
| Title: | Macro-Modeling of Electromagnetic Domains Exhibiting Geometric and Material Uncertainty |
| Abstract: | A methodology is presented for the development of stochastic electromagnetic macromodels for domains exhibiting geometric and material uncertainty. Focusing on the case of domains exhibiting geometric/material invariance along one of the axes of the reference coordinate system, the methodology makes use of the theory of polynomial chaos expansion and the concept of a global impedance/admittance matrix relationship defined over a circular surface enclosing the crosssectional geometry of the domain of interest. The result is a stochastic global impedance/admittance matrix, defined on the enclosing circular surface, whose elements are truncated polynomial chaos expansions over the random space defined by the independent random variables that parameterize the geometric and material uncertainty inside the domain. Use is made of sparse Smolyak grids to reduce the computational cost of constructing the stochastic macro-model. Numerical examples are used to demonstrate some of the attributes of the proposed stochastic macro-models to the numerical solution of electromagnetic scattering problems by an ensemble of cylindrical targets exhibiting uncertainty in their shape and relative positioning. |
| Author(s): | J. S. Ochoa , A. C. Cangellaris |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 818 KB |
| Title: | Finite Difference Time Domain Diakoptic Strategies |
| Abstract: | In many applications, it may be advisable to “tear apart” the computational domain into several sub-domains separated by “seams,” each one treated separately. The sub-domains are then sewn back together at appropriate stages of the computation. Three main diakoptic strategies have been developed in the recent past. Out of these, the diakoptics on-the-fly strategy can serve the purpose of parallelizing a FDTD process over several processors, each of which being responsible for the treatment of a certain sub-domain, as presented below. |
| Author(s): | O. Harpaz, R. Kastner |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 1802 KB |
| Title: | An Electromagnetic Compatibility Problem via Unscented Transform and Stochastic Collocation Methods |
| Abstract: | This paper aims to illustrate the current interest about the use of stochastic techniques for electromagnetic compatibility (EMC) issues. This problem may be handled from various methods. First, we may focus on the Monte Carlo (MC) formalism but other techniques have been implemented more recently (the unscented transform, UT, or stochastic collocation, SC, for instance). This work deals with solving a stochastic EMC problem (transmission line) with the UT and SC techniques and to compare them with the reference MC results. |
| Author(s): | S. Lalléchère, P. Bonnet, I. El Baba, F. Paladian |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 1499 KB |
| Title: | Combining the CORS and BiCORSTAB Iterative Methods with MLFMA and SAI Preconditioning for Solving Large Linear Systems in Electromagnetics |
| Abstract: | We report on experiments with a novel family of Krylov subspace methods for solving dense, complex, non-Hermitian systems of linear equations arising from the Galerkin discretization of surface integral equation models in Electromagnetics. By some experiments on realistic radar-cross-section calculation, we illustrate the numerical efficiency of the proposed class of algorithms also against other popular iterative techniques in use today. |
| Author(s): | N. Carpentieri, Y. F. Jing, T. Z. Huang, W. C. Pi, X. Q. Sheng |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 694 KB |
| Title: | Investigating the Composite Step Biconjugate A-Orthogonal Residual Method for Non-Hermitian Dense Linear Systems in Electromagnetics |
| Abstract: | An interesting stabilizing variant of the biconjugate A-orthogonal residual (BiCOR) method is investigated for solving dense complex non-Hermitian systems of linear equations arising from the Galerkin discretization of surface integral equations in electromagnetics. The novel variant is naturally based on and inspired by the composite step strategy employed for the composite step biconjugate gradient method from the point of view of pivot-breakdown treatment when the BiCOR method has erratic convergence behaviors. Besides reducing the number of spikes in the convergence history of the norm of the residuals to the greatest extent, the present composite step BiCOR method can provide some further practically desired smoothing behavior towards stabilizing the numerical performance of the BiCOR method in the case of irregular convergence. |
| Author(s): | Y. F Jing, T. Z. Huang, B. Carpentieri, Y. Duan |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 544 KB |
| Title: | Advanced Techniques for Efficient Modeling of Electrically Large Structures on Desktop PCs |
| Abstract: | The method of moments (MoM), applied to surface integral equations (SIEs) in the frequency domain, enables very accurate analysis of composite metallic and dielectric structures. Particularly, on a desktop PC, the electrical size of solvable problems is very limited by memory and time resources. This limit can be significantly extended by using advanced techniques, which are shortly revealed. The focus of the paper is to present results that illustrate current possibilities of MoM/SIEs solution on a desktop PC: (1) monostatic RCS of a cube of side 80 ?, (2) beam steering of an array of 30 by 30 microstrip patch antennas at 9.2 GHz, and (3) beam steering of 4 by 4 patch antennas at 5 GHz, placed on a 19 m long helicopter. |
| Author(s): | B. M. Kolundzija, M. S. Tasic, D. I. Olcan, D. P. Zoric, S. M. Stevanetic |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 998 KB |
| Title: | Distributed-Memory Parallelization of an Explicit Time-Domain Volume Integral Equation Solver on Blue Gene/P |
| Abstract: | Two distributed-memory schemes for efficiently parallelizing the explicit marching-onin- time based solution of the time domain volume integral equation on the IBM Blue Gene/P platform are presented. In the first scheme, each processor stores the time history of all source fields and only the computationally dominant step of the tested field computations is distributed among processors. This scheme requires all-to-all global communications to update the time history of the source fields from the tested fields. In the second scheme, the source fields as well as all steps of the tested field computations are distributed among processors. This scheme requires sequential global communications to update the time history of the distributed source fields from the tested fields. Numerical results demonstrate that both schemes scale well on the IBM Blue Gene/P platform and the memoryefficient second scheme allows for the characterization of transient wave interactions on composite structures discretized using three million spatial elements without an acceleration algorithm. |
| Author(s): | A. Al-Jarro, M. Cheeseman, H. Bagci |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 961 KB |
| Title: | On-The-Fly Mesh Generation for a High Performance Physical Optics Radar Backscattering Simulator |
| Abstract: | In this paper, we present a radar backscattering simulator based on the method of physical optics (PO). Our simulation tool closely intertwines the tessellation of the simulation geometry with the physical optics method kernel, which enables on-the-fly refinement of input model data while still yielding high precision and computational performance. The algorithms for the physical optics method as well as the parallelization scheme will be presented. Also, performance comparisons will be shown and explained, both in regard to accuracy of the results and computation time. |
| Author(s): | S. Hegler, R. Hahnel, D. Plettemeier |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 763 KB |
| Title: | Exploiting FPGAs and GPUs for Electromagnetics Applications: Interferometric Imaging in Random Media Case Study |
| Abstract: | There is a growing need for reliable and efficient numerical methods for electromagnetic applications. This is important for addressing the complex designs with fine features on electrically large platforms. As designs become more complex, a good prediction of overall system performance becomes essential for cost reduction especially in the conceptualization stage. Researchers have attempted to address this issue by developing hybrid methods based on asymptotic techniques that can avoid the numerical inefficiency while maintaining high degrees of accuracy. Another approach is to implement fast computational methods that utilize parallel computing platforms. This paper focuses on the latter; i.e. by investigating the use of field programmable gate arrays (FPGA) and general purpose graphics processing units (GPGPU) as coprocessors to parallelize numerically challenging problems. The weaknesses and strengths of both platforms will be investigated in the context of their ease of use, efficiency, and potential for accelerated computations. |
| Author(s): | E. El-Araby, O. Kilic, V. Dang |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 1109 KB |
| Title: | Rigorous Analysis of Double-Negative Materials with the Multilevel Fast Multipole Algorithm |
| Abstract: | We present rigorous analysis of double-negative materials (DNMs) with surface integral equations and the multilevel fast multipole algorithm (MLFMA). Accuracy and efficiency of numerical solutions are investigated when DNMs are formulated with two recently developed formulations, i.e., the combined tangential formulation (CTF) and the electric and magnetic current combined-field integral equation (JMCFIE). Simulation results on canonical objects are consistent with previous results in the literature on ordinary objects. MLFMA is also parallelized to solve extremely large electromagnetics problems involving DNMs. |
| Author(s): | Ö. Ergül, L. Gürel |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 2980 KB |
| Title: | Analysis of ElectromagneticWave Propagation in Frequency Bands of Nonlinear Metamaterials |
| Abstract: | Electromagnetic wave propagation phenomena in nonlinear metamaterials are investigated for waves propagating either in the left-handed frequency band or in the frequency band gaps. In the left-handed band, we implement directly the reductive perturbation method to Faraday’s and Amp´ere’s laws and derive a second-and a thirdorder nonlinear Schr¨odinger (NLS) equation, describing solitons of moderate and ultra-short pulse widths, respectively. Then, we find necessary conditions and derive exact bright and dark soliton solutions of these equations. On the other hand, in the frequency band gaps with negative linear effective permittivity and positive permeability (where linear electromagnetic waves are evanescent), we derive two short-pulse equations (SPEs) for the high- and low-frequency band gaps. The structure of the SPEs solutions is discussed, and connections with the NLS soliton solutions are presented. Numerical simulations of the SPEs solutions are included and compared with those of the reduced wave equations. Directions towards the modelling of wave propagation in nonlinear chiral metamaterials are pointed out. |
| Author(s): | N. L. Tsitsas |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 733 KB |
| Title: | Optical Aspects of the Interaction of Focused Beams with Plasmonic Nanoparticles |
| Abstract: | In this study, the interaction of nanoparticles with focused beams of various angular spectra is investigated. This study demonstrates that the focused light can be used to manipulate the near-field radiation around nanoparticles. It is shown that suppressing strong lobes and enhancing weaker lobes is possible for spherical particles by altering the angular spectrum. This can have an impact on plasmonic applications where strong and weak fields are desired at specific locations. |
| Author(s): | K. Sendur |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 782 KB |
| Title: | Surface Integral Equation Solvers for Large-Scale Conductors, Metamaterials and Plasmonic Nanostructures |
| Abstract: | Surface integral equation (SIE) approaches for the accurate solution of different problems in computational electromagnetics are addressed. First, an efficient message passing interface (MPI)/OpenMP parallel implementation of the multilevel fast multipole algorithm-fast Fourier transform (MLFMA-FFT) is presented for the solution of large-scale conducting bodies. By combining the high scalability of the fast multipole method-FFT (FMM-FFT) with the high efficiency of MLFMA, challenging problems up to one billion unknowns are solved using a parallel supercomputer. Second, looking for the extension of these rigorous approaches to new demanded areas, the SIE method is successfully applied to the solution of left-handed metamaterials and plasmonic nanostructures. Numerical examples are presented to confirm the validity and versatility of this approach for the accurate resolution of problems in the context of leading-edge nanoscience and nanotechnology applications. |
| Author(s): | J. M. Taboada, M. G. Araújo, J. Rivero, L. Landesa, F. Obelleiro |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 961 KB |
| Title: | Optimal Location of Multi-Antenna Systems - Influence of Noise-Corrupted Data |
| Abstract: | This paper describes the development of an antenna synthesis procedure for determining the optimal location of 2D array configurations. An inverse scattering algorithm based on a conjugate gradient method is used. The influence of noise-corrupted data on the results is investigated. |
| Author(s): | M. Zoppi, C. Dedeban, Ch. Pichot, S. Selleri, G. Pelosi |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 1610 KB |
| Title: | CUDA-OpenGL Interoperability to Visualize Electromagnetic Fields Calculated by FDTD |
| Abstract: | In this contribution, a compute unified device architecture (CUDA) implementation of a two-dimensional finite-difference time-domain (FDTD) program is presented along with the OpenGL interoperability to visualize electromagnetic fields as an animation while an FDTD simulation is running. CUDA, which runs on a graphics processing unit (GPU) card, is used for electromagnetic field data generation and image manipulation, while OpenGL is used to draw field distribution on the screen. Since CUDA and OpenGL both run on GPU and share data through common memory in the framebuffer, the CUDA-OpenGL interoperability is very efficient in visualization of electromagnetic fields. Step by step details of implementation of this interoperability are demonstrated. |
| Author(s): | V. Demir, A. Z. Elsherbeni |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 2 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 748 KB |