Browsing by Subject "Combined-field integral equation (CFIE)"

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    Combined-field solution of composite geometries involving open and closed conducting surfaces
    (IEEE, 2005-04) Ergül, Özgür; Gürel, Levent
    Combined-field integral equation (CFIE) is modified and generalized to formulate the electromagnetic problems of composite geometries involving both open and closed conducting surfaces. These problems are customarily formulated with the electric-field integral equation (EFIE) due to the presence of the open surfaces. With the new definition and application of the CFIE, iterative solutions of these problems are now achieved with significantly improved efficiency compared to the EFIE solution, without sacrificing the accuracy. © 2005 ACES.
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    Contamination of the accuracy of the combined-field integral equation with the discretization error of the magnetic-field integral equation
    (Institute of Electrical and Electronics Engineers, 2009) Gürel, Levent; Ergül, Özgür
    We investigate the accuracy of the combined-field integral equation (CFIE) discretized with the Rao-Wilton-Glisson (RWG) basis functions for the solution of scattering and radiation problems involving three-dimensional conducting objects. Such a low-order discretization with the RWG functions renders the two components of CFIE, i.e., the electric-field integral equation (EFIE) and the magnetic-field integral equation (MFIE), incompatible, mainly because of the excessive discretization error of MFIE. Solutions obtained with CFIE are contaminated with the MFIE inaccuracy, and CFIE is also incompatible with EFIE and MFIE. We show that, in an iterative solution, the minimization of the residual error for CFIE involves a breakpoint, where a further reduction of the residual error does not improve the solution in terms of compatibility with EFIE, which provides a more accurate reference solution. This breakpoint corresponds to the last useful iteration, where the accuracy of CFIE is saturated and a further reduction of the residual error is practically unnecessary.
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    Hybrid CFIE-EFIE solution of composite geometries with coexisting open and closed surfaces
    (IEEE, 2005) Ergül, Özgür; Gürel, Levent
    The combined-field integral equation (CFIE) is employed to formulate the electromagnetic scattering and radiation problems of composite geometries with coexisting open and closed conducting surfaces. Conventional formulations of these problems with the electric-field integral equation (EFIE) lead to inefficient solutions due to the ill-conditioning of the matrix equations and the internal-resonance problems. The hybrid CFIE-EFIE technique introduced in this paper, based on the application of the CFIE on the closed surfaces and EFIE on the open surfaces, significantly improves the efficiency of the solution.