Nie Xiaochun
Email Address
tslniexc@nus.edu.sg
21 results
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Publication Efficient analysis of electromagnetic scattering and radiation from patches on finite, arbitrarily curved, grounded substrates(2004-05) Yuan, N.; Yeo, T.S.; Nie, X.C.; Li, L.W.; Gan, Y.B.; TEMASEK LABORATORIES; ELECTRICAL & COMPUTER ENGINEERINGA precorrected-fast Fourier transform (FFT) accelerated surface integral equation approach formulated using the homogeneous medium Green's function is presented for the analysis of patch arrays on finite, arbitrarily shaped, grounded substrate. The integral equation is solved by the method of moments, and the precorrected-FFT method is applied to reduce the memory requirement and computational complexity of the solution procedure. The memory required for this algorithm is O(N1.5), and the computational complexity is N iterW1.5log N, where N is the number of unknowns and Niter is the iteration number. Numerical results are presented to demonstrate the accuracy and capability of the method.Publication Precorrected-FFT algorithm for solving combined field integral equations in electromagnetic scattering(2002) Nie, X.-C.; Li, L.-W.; Yuan, N.; ELECTRICAL & COMPUTER ENGINEERING; SINGAPORE-MIT ALLIANCEThe precorrected-FFT method is applied in this paper to solve the combined field integral equation (CFIE) for scattering by arbitrarily shaped three-dimensional conductors. The object is first discretized using triangular elements with the Rao-Wilton-Glisson (RWG) basis functions. The source singularities on the original triangular meshes are then projected onto uniform rectangular grids, which enables the calculation of the resultant matrix-vector product to be performed by using the fast Fourier transforms. The memory requirement and computational complexity of the resulting algorithm are of O(N1.5) and O(N1.5 log N), respectively, where N denotes the number of unknowns. In addition, the employment of CFIE eliminates the interior resonance problem suffered by both the electric field integral equation (EFIE) and the magnetic field integral equation (MFIE) and thus significantly improves the convergence of the iterative solution. A unique advantage of the present method is that the computational expense per iteration of CFIE is almost the same as that of EFIE. This fast algorithm renders problems associated with electromagnetic scattering by large complex objects be handled on a normal personal computer.Publication A precorrected-FFT approach for capacitance extraction of general three-dimensional structures(2001) Nie, X.; Li, L.; Yuan, N.; ELECTRICAL & COMPUTER ENGINEERING; SINGAPORE-MIT ALLIANCEA precorrected fast Fourier transforms (FFT) method was used for capacitance extraction of general three-dimensional structures. The linear system arising from the discretization was solved by a generalized conjugate residual iterative technique. This technique required O(N) memory storage and O(N log N) operations to perform a potential calculation.Publication Efficient numerical modeling of large-scale microstrip structures(2002) Yuan, N.; Yeo, T.S.; Nie, X.C.; Li, L.W.; ELECTRICAL & COMPUTER ENGINEERING; SINGAPORE-MIT ALLIANCEThe precorrected-FFT method is employed to eliminate the need to store the impedance matrix and accelerate the matrix-vector product. In the approach, the mixed potential integral equation (MPIE) is developed in the spatial domain and discretized using triangular elements with RWG basis functions. The resulting algorithm reduces the memory requirement and computational cost to O(N) and O(N log N) respectively. Thus, numerical examples are presented to demonstrate the efficiency and accuracy of the method.Publication Accurate analysis of conformal antenna arrays with finite and curved frequency selective surfaces(2007-10-01) Yuan, N.; Nie, X.-C.; Gan, Y.-B.; Yeo, T.-S.; Li, L.-W.; TEMASEK LABORATORIES; ELECTRICAL & COMPUTER ENGINEERINGIn this paper, a full-wave volume-surface integral equation approach is presented for the analysis of conformal microstrip antenna arrays with finite curved frequency selective surface (FSS) radomes. The volume integral equation is applied to the dielectric region of the composite structure, while the surface integral equation is used on the conductive surface. The integral equations are solved using the method of moments (MoM), with the precorrected-FFT (P-FFT) method used to reduce the memory requirement and accelerate the matrix-vector products in the iterative solution of the equation. With this method, FSSs and antennas of arbitrary shape and finite size can be modelled and the effects of the FSS on the characteristics of the antenna can be accurately investigated. © 2007 VSP.Publication A parallel analysis of the scattering from inhomogeneous dielectric bodies by the volume integral equation and the precorrected-FFT algorithm(2004-07-05) Wang, Y.-J.; Nie, X.-C.; Li, L.-W.; Li, E.-P.; TEMASEK LABORATORIES; ELECTRICAL & COMPUTER ENGINEERINGIn this paper, a parallel implementation of the precorrected fast Fourier transform (FFT) algorithm is presented to efficiently solve the volume-integral equation for scattering from inhomogeneous dielectric objects. Several examples are given to demonstrate the efficiency and correctness of the message-passing interface (MPI)-based parallelization algorithm. © 2004 Wiley Periodicals, Inc.Publication A fast volume-surface integral equation solver for scattering from composite conducting-dielectric objects(2005-02) Nie, X.-C.; Yuan, N.; Li, L.-W.; Gan, Y.-B.; Yeo, T.S.; TEMASEK LABORATORIES; ELECTRICAL & COMPUTER ENGINEERINGThis paper presents a fast hybrid volume-surface integral equation approach for the computation of electromagnetic scattering from objects comprising both conductors and dielectric materials. The volume electric field integral equation is applied to the material region and the surface electric field integral equation is applied on the conducting surface. The method of moments (MoM) is used to convert the integral equation into a matrix equation and the precorrected-FFT (P-FFT) method is employed to reduce the memory requirement and CPU time for the matrix solution. The present approach is sufficiently versatile in handling problems with either open or closed conductors, and dielectric materials of arbitrary inhomogeneity, due to the combination of the surface and volume electric field integral equations. The application of the precorrected-FFT method facilitates the solving of much larger problems than can be handled by the conventional MoM. © 2005 IEEE.Publication Precorrected-FFT solution of the volume integral equations for inhomogeneous dielectric bodies(2003) Nie, X.C.; Li, L.W.; Yuan, N.; Yeo, T.S.; Gan, Y.B.; TEMASEK LABORATORIES; ELECTRICAL & COMPUTER ENGINEERINGThe precorrected-FFT method is applied to the fast solution of the volume integral equation for lossy, inhomogeneous dielectric bodies. The volume of the dielectric body is discretized into tetrahedron elements and the SWG basis functions are employed to expand the unknown electric flux density. The basis functions are then projected onto a uniform grid surrounding the nouniform mesh, enabling the FFTs to be used to speed up the matrix-vector multiplies in the iterative solution of the matrix equation. The resultant method has a computational complexity and memory requirement of O(N log N) and O(N) respectively.Publication A fast combined field volume integral equation solution to EM scattering by 3-D dielectric objects of arbitrary permittivity and permeability(2006-03) Nie, X.-C.; Yuan, N.; Li, L.-W.; Gan, Y.-B.; Yeo, T.S.; TEMASEK LABORATORIES; ELECTRICAL & COMPUTER ENGINEERINGA fast solution to the combined field volume integral equation (CFVIE) for electromagnetic scattering by large three-dimensional dielectric bodies of arbitrary permittivity and permeability is presented. The CFVIE is formulated in the region of the scatterers by expressing the total fields as the sum of the incident wave and the radiated wave due to both the electric and magnetic polarization currents. The resultant integral equation is solved using the method of moments (MoM). Then the precorrected fast Fourier transform (P-FFT) method is applied to reduce the memory requirement and accelerate the matrix-vector multiplication in the MoM solution. In the implementation of the P-FFT method, two sets of projection operators are constructed respectively for the projections of the electric sources and magnetic sources. In addition, two sets of interpolation operators are also applied respectively for the computation of the vector/scalar potentials and the curl of the vector potentials in the support of the testing functions. The resultant method has a memory requirement O(N) and a computational complexity of O(Nlog N) respectively, where N denotes the number of unknowns. © 2006 IEEE.Publication Analysis of scattering from composite conducting and dielectric targets using the precorrected-FFT algorithm(2003) Yuan, N.; Yeo, T.S.; Nie, X.C.; Li, L.W.; Gan, Y.B.; TEMASEK LABORATORIES; ELECTRICAL & COMPUTER ENGINEERINGA precorrected-FFT algorithm is presented for the calculation of electromagnetic scattering from conducting objects coated with lossy materials. The problem is formulated using an EFIE-PMCHW formulation, which employs the electric field integral equation (EFIE) for conducting objects and the PMCHW formulation for dielectric objects. The integral equations are then discretized by the method of moments (MoM). in which the conducting and dielectric surfaces are represented by triangular patches and the unknown equivalent electric and magnetic currents are expanded using the RWG basis functions. The resultant matrix equation is solved iteratively and the precorrected-FFT method is used to speed up the matrix-vector products in iterations as well as to reduce the memory requirement. Numerical examples are presented to validate the implementation and to demonstrate the accuracy of the method.
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