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Higher Order Modeling In the BEM/FEM Hybrid FormulationHybrid formulations using low order curl-conforming bases to represent the total electric field within a finite element region and low order divergence-conforming bases to represent equivalent electric and magnetic currents on the boundary are well known. However, higher-order divergence and curl-conforming bases have been shown to provide significant benefits in convergence rates and accuracy when employed in strictly integral equation and strictly finite element formulations. In this paper, a hybrid electric field formulation employing higher order bases is presented. The paper addresses benefits and issues associated with using higher order divergence-and curl-conforming bases in the hybrid finite element/boundary element electric field formulation. The method of singularity subtraction may be used to compute the self terms of the boundary integral when the bases are of low order. But this method becomes laborious and requires great care when the divergence conforming bases are of higher order. In order to handle these singularities simply and accurately, a generalized Gaussian quadrature method is employed in which the expansion functions account for the singularity. In preliminary tests of the higher order hybrid formulation, the equivalent electric current induced by scattering of a plane wave from a square dielectric cylinder is examined. Accurate results are obtained using only a two-triangle mesh when the current basis is of order 4 or 5. Additional results are presented comparing the error obtained using higher order bases to that obtained using lower order bases when the number of unknowns is approximately equal. Also, convergence rates obtained with higher order bases are compared to those obtained with lower order bases for selected sample problems.
Document ID
20000110099
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Fink, Patrick W.
(NASA Johnson Space Center Houston, TX United States)
Wilton, Don R.
(Houston Univ. TX United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 2000
Subject Category
Communications And Radar
Meeting Information
Meeting: National Radio Science Meeting
Location: Boulder, CO
Country: United States
Start Date: January 4, 2000
End Date: January 8, 2000
Sponsors: International Union of Radio Science
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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