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Title: DOMAIN DECOMPOSITION STRATEGIES FOR SOLVING THE MAXWELL EQUATIONS ON DISTRIBUTED PARALLEL ARCHITECTURES
Abstract: Domain decomposition strategies for solving hyperbolic systems of partial differential equations on distributed-memory parallel computing platforms are investigated. The logically-rectangular computational domain is divided either one, two, or three dimensionally into a series of computational blocks, and each block is assigned to a single processor. Theoretical predictions using standard parallel performance models indicate that higher-dimensional decompositions provide superior parallel program performance in terms of scalability. The theory is tested using a finite-volume time-domain (FVTD) Maxwell equations solver to compute the electromagnetic fields inside a rectangular waveguide using various grid sizes and processor numbers on three different parallel architectures- the Intel Paragon, the IBM SP2, and the Cray T3D. The specific performance of the FVTD algorithm on the three machines is investigated, the relation between processor connection topology and message passing performance of a typical grid-based hyperbolic equation solver are identified, and the results are used to augment the classical parallel performance model. Although clear performance trends emerge in terms of the dimensionality of the decomposition, results indicate that higher-dimensional decompositions do not always provide superior parallel performance. [Vol. 12, No. 3 (1997), pp 4-15]
Author(s): Douglas C. Blake, Thomas A. Buter
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
Download Link:Click here to download PDF     File Size: 892 KB

Title: MOMENT METHOD SURFACE PATCH AND WIRE GRID ACCURACY IN THE COMPUTATION OF NEAR FIELDS
Abstract: The accuracy of surface patch and wire grid moment method models for the of near fields is investigated. A sphere and a flat plate with plane wave illumination are examined. It is found that wire grids exhibit stronger near field anomalies than surface patches, which have the current more distributed over the surface. Nevertheless, good results can be obtained with a wire grid, provided that a small distance from the wire grid surface is maintained The surface patch results are obtained using the Junction code. Wire grid results are with both the MBC and NEC codes. Validation the sphere is by comparison with an exact solution obtained from the NECBSC code. [Vol. 12, No. 3 (1997), pp 16-25]
Author(s): Robert Paknys, Leslie R. Raschkowan
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
Download Link:Click here to download PDF     File Size: 578 KB

Title: USING THE FDTD METHOD TO MODEL THE REFLECTION COEFFICIENT OF A VIVALDI TAPERED SLOT ANTENNA FED THROUGH A PLANAR BALUN
Abstract: In this paper, the Time-Domain (FDTD) method was used to determine the reflection coefficient vs. frequency of a Vivaldi Tapered Dual-Slot Antenna fed through a planar balun. The reflection coefficient at the input port of the feed stripline was determined through the separate computation of the reflection coefficient of representation of the antenna section and the scattering matrix of the balun, assuming that the electromagnetic coupling between these sections was negligible. Experimental results, which were obtained on a prototype of this structure, confirmed the validity of the proposed approach and demonstrate that the coupling of the model. [Vol. 12, No. 3 (1997), pp 26-30]
Author(s): G. Biffi Gentili, R Braccini, M. Leoncini
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
Download Link:Click here to download PDF     File Size: 308 KB

Title: FINITE-DIFFERENCE TIME-DOMAIN MODELING OF LIGHT-TRAPPING IN SOLAR CELLS
Abstract: To maximize light-trapping, the absorption of light in the solar cell is maximized. The ways to increase light-trapping are to texture the surfaces of the solar cell and to use anti-reflection coatings. The power spectrum of sunlight also plays an important role in light-trapping. In general, a solar cell consists of multiple layers of dielectric materials. Each dielectric has a complicated surface texture geometry to increase light-trapping. This paper concentrates on solving Maxwell's equations for the general solar cell configuration under illumination from the sun. The absorption and maximum achievable current density are calculated and used to quantify light-trapping in a given solar cell design. Thin solar cells promise to yield higher current collection than thick solar cells at a lower cost [1]. Low cost solar cells are usually characterized by short diffusion length semiconductors. Most minority carriers created within the distance equal to the diffusion length contribute to the electrical current of a solar cell. Hence, the solar cell must be thin when low quality materials are used. As solar cells decrease in size, the ray-trace model becomes inaccurate as previously demonstrated in [2]. A full-wave Finite-Difference Time-Domain (FDTD) light-trapping model is demonstrated to accurately study light-trapping of thin-film solar cells. [Vol. 12, No. 3 (1997), pp 31-42]
Author(s): Todd Marshall, Melinda Piket-May
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
Download Link:Click here to download PDF     File Size: 872 KB

Title: MODELLING EDDY CURRENTS IN UNBOUNDED STRUCTURES USING THE IMPEDANCE METHOD
Abstract: In this paper extensions to the impedance network method are presented. In particular the method has been applied to problems with boundaries extending to infinity. The infinite boundary condition can also be applied to lines of symmetry in the given geometry. Two dimensional surface models have been verified by comparison of numerical and experimental results in which the potential was measured along the edge of copper sheeting of various shapes located in a uniform, quasi-static magnetic field. The method has potential for modelling three dimensional structures including anisotropic earth planes, arbitrarily shaped buried objects, and both finite and infinitely long faults, dykes, pipes, cylinders and cracks. [Vol. 12, No. 3 (1997), pp 43-49]
Author(s): Daniel James Daniel James, David V. Thiel
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
Download Link:Click here to download PDF     File Size: 479 KB

Title: VERIFICATION OF SOFTWARES FOR ELECTROMAGNETIC FIELD ANALYSIS USING MODELS PROPOSED BY INVESTIGATION COMMITTEES IN IEE OF JAPAN
Abstract: In order to investigate methods for analyzing electromagnetic fields and to compare the accuracy and the CPU time of various codes and so on, investigation committees were set up in IEE of Japan. In this paper, the activities of various investigation committees relating electromagnetic field analysis are described from the viewpoint of the verification of software. [Vol. 12, No. 3 (1997), pp 50-61
Author(s): Norio Takahashi
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
Download Link:Click here to download PDF     File Size: 793 KB