Ergül, ÖzgürGürel, Levent2016-02-082016-02-082007-08http://hdl.handle.net/11693/27071Date of Conference: 30-31 Aug. 2007Conference name: 2007 Computational Electromagnetics WorkshopWe consider the solution of electromagnetic scattering problems involving relatively large dielectric objects with moderate and low contrasts. Three-dimensional objects are discretized with Rao-Wilton-Glisson functions and the scattering problems are formulated with surface integral equations. The resulting dense matrix equations are solved iteratively by employing the multilevel fast multipole algorithm. We compare the accuracy and efficiency of the results obtained by employing various integral equations for the formulation of the problem. If the problem size is large, we show that a combined formulation, namely, electric-magnetic current combined-field integral equation, provides faster iterative convergence compared to other formulations, when it is accelerated with an efficient block preconditioner. For low-contrast problems, we introduce various stabilization procedures in order to avoid the numerical breakdown encountered in the conventional surface formulations. © 2007 IEEE.EnglishAircraftElectromagnetic wave scatteringElectromagnetismFunction evaluationIterative methodsMagnetismScatteringSolutionsThree dimensionalBreakdown (BD)Combined field integral equation (CFIE)Computational electromagnetics (CEM)Convergence (mathematics)Dense matricesDielectric objectsElectromagnetic scattering problemsIn orderMagnetic currentsMultilevel fast multipole algorithm (MLFMA)preconditionerProblem sizesRao-Wilton-Glisson (RWG) functionsScattering problem (SP)Surface formulationsSurface integral equationsThree-dimensional (3-D) objectsIntegral equationsConference Paper10.1109/CEM.2007.4387652