The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Weng Cho Chew - One of the best experts on this subject based on the ideXlab platform.
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a calderon preconditioner for the electric field integral equation with Layered Medium green s function
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Weng Cho ChewAbstract:A Calderon preconditioner is developed for the analysis of electromagnetic scattering of perfect electrically conducting (PEC) objects embedded in a Layered Medium. The electric field integral equation (EFIE) is formulated with the kernel of Layered Medium Green's function to account for the effects from the multiLayered background. The Calderon projector is derived based on the general source-field relationship and the extinction theorem for inhomogeneous environment in electromagnetic theory. The Calderon identities can be naturally deduced based on this projector, which is then leveraged to precondition the EFIE with Layered kernel. An alternative implementation is then proposed to make the implementation of the preconditioner as efficient as the one in free space. Different numerical examples are designed to show the performance of the preconditioner, where the objects are located in different positions with respect to the Layered Medium, or different types of excitation are adopted. It is shown that the proposed effective and robust preconditioner makes the EFIE system converge rapidly in all cases, independent of the discretization density.
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Calderón preconditioned PMCHWT equation for Layered Medium problems
2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Weng Cho ChewAbstract:Electromagnetic scattering by dielectric objects in the presence of a Layered Medium is investigated by applying the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) equation combined with the Layered Medium Green's function. Due to the electric field integral equation (EFIE) operator involved, the spectrum of the PMCHWT equation is also undesired. When the surface is densely discretized, the condition of the resulting matrix is extremely bad. An effective Calder´ on preconditioner is developed in this paper to improve the convergence. Different from its free space counterpart, the Calder´ on identities for inhomogeneous Medium need to be re-derived. It is shown from numerical examples that the convergence of the PMCHWT system in Layered Medium can be significantly improved by using the proposed Calder´ on preconditioner.
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Calderón Preconditioned PMCHWT Equations for Analyzing Penetrable Objects in Layered Medium
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Weng Cho ChewAbstract:We study Calderon preconditioners for analyzing electromagnetic scattering by penetrable objects in a Layered Medium. To account for the scattering effects of the multiLayered background, the Layered Medium Green's function is adopted in the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) method. However, similar to the free-space case, the spectrum of the resulting equation is undesirable. This leads to a slow convergence of an iterative solver, especially when the geometry is densely meshed. To improve the convergence, a highly effective preconditioner is proposed. Different from its free-space counterpart, the preconditioning operator is constructed based on the Calderon identities for inhomogeneous Medium. To reduce the relatively high construction cost of the preconditioning operator, several alternative simplified schemes are proposed and analyzed. Finally, the performances of different preconditioners are examined and compared carefully through different numerical examples. It is shown that the convergence of the PMCHWT system in a Layered Medium can be significantly improved by using the proposed Calderon preconditioners.
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Analysis of scattering by PEC objects in Layered Medium with Calderón preconditioner
2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Min Meng, Weng Cho ChewAbstract:Electromagnetic scattering by perfect electrically conducting (PEC) objects in a Layered Medium is studied in this paper. The Layered Medium Green’s function is adopted as the kernel of the electric field integral equation (EFIE) so that the effects from the multiLayered background can be accounted for automatically. However, the spectrum of the EFIE with this kernel, is unfortunately undesirable. This leads to slow convergence of the iterative solution. To improve the convergence, the Calderon identities are derived and leveraged to precondition the EFIE. By utilizing Buffa-Christiansen (BC) basis function in discretizing the preconditioning operator, the preconditioner can be made completely multiplicative. Different numerical examples are designed to show the performance of the preconditioner. It is shown that the proposed preconditioner makes the EFIE system with Layered kernel converge rapidly, independent of the discretization density.
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a new green s function formulation for modeling homogeneous objects in Layered Medium
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Yongpin Chen, Weng Cho Chew, Li Jun JiangAbstract:A new Green's function formulation is developed systematically for modeling general homogeneous (dielectric or magnetic) objects in a Layered Medium. The dyadic form of the Green's function is first derived based on the pilot vector potential approach. The matrix representation in the moment method implementation is then derived by applying integration by parts and vector identities. The line integral issue in the matrix representation is investigated, based on the continuity property of the propagation factor and the consistency of the primary term and the secondary term. The extinction theorem is then revisited in the inhomogeneous background and a surface integral equation for general homogeneous objects is set up. Different from the popular mixed potential integral equation formulation, this method avoids the artificial definition of scalar potential. The singularity of the matrix representation of the Green's function can be made as weak as possible. Several numerical results are demonstrated to validate the formulation developed in this paper. Finally, the duality principle of the Layered Medium Green's function is discussed in the appendix to make the formulation succinct.
Yongpin Chen - One of the best experts on this subject based on the ideXlab platform.
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a hybrid fem mom method for 3 d electromagnetic scattering in Layered Medium
IEEE Transactions on Antennas and Propagation, 2016Co-Authors: Yi Ren, Qing Huo Liu, Yongpin ChenAbstract:Accurate and efficient prediction of electromagnetic scattering from inhomogeneous objects in Layered Medium is one of the most challenging issues in engineering applications. This paper presents the first 3-D higher order hybrid finite-element method (FEM) and method of moments (MoM) for the accurate modeling of inhomogeneous dielectric objects in multiLayered Medium. The main challenges of this paper include: 1) the integration of these algorithms for Layered Medium and 2) the higher order computational approach involved in Layered Medium for high efficiency. In the proposed method, the MoM with the Layered Medium dyadic Green’s function is used as the exact radiation boundary condition in an inhomogeneous background, and the FEM is applied to model the inhomogeneous objects. Furthermore, the higher order maximally orthogonal basis functions with curl-conforming and divergence-conforming properties are used in the FEM and MoM, respectively to improve the modeling capability of this algorithm. For 3-D inhomogeneous objects scattering in multiLayered Medium, this new method requires a much more tightly truncated simulation domain than the traditional FEM, and provides much higher flexibility than the pure surface integral equation method. Finally, some numerical results are provided to validate the accuracy, efficiency, and flexibility of this method.
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A Hybrid FEM/MoM Method for 3-D Electromagnetic Scattering in Layered Medium
IEEE Transactions on Antennas and Propagation, 2016Co-Authors: Yi Ren, Qing Huo Liu, Yongpin ChenAbstract:Accurate and efficient prediction of electromagnetic scattering from inhomogeneous objects in Layered Medium is one of the most challenging issues in engineering applications. This paper presents the first 3-D higher order hybrid finite-element method (FEM) and method of moments (MoM) for the accurate modeling of inhomogeneous dielectric objects in multiLayered Medium. The main challenges of this paper include: 1) the integration of these algorithms for Layered Medium and 2) the higher order computational approach involved in Layered Medium for high efficiency. In the proposed method, the MoM with the Layered Medium dyadic Green’s function is used as the exact radiation boundary condition in an inhomogeneous background, and the FEM is applied to model the inhomogeneous objects. Furthermore, the higher order maximally orthogonal basis functions with curl-conforming and divergence-conforming properties are used in the FEM and MoM, respectively to improve the modeling capability of this algorithm. For 3-D inhomogeneous objects scattering in multiLayered Medium, this new method requires a much more tightly truncated simulation domain than the traditional FEM, and provides much higher flexibility than the pure surface integral equation method. Finally, some numerical results are provided to validate the accuracy, efficiency, and flexibility of this method.
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a calderon preconditioner for the electric field integral equation with Layered Medium green s function
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Weng Cho ChewAbstract:A Calderon preconditioner is developed for the analysis of electromagnetic scattering of perfect electrically conducting (PEC) objects embedded in a Layered Medium. The electric field integral equation (EFIE) is formulated with the kernel of Layered Medium Green's function to account for the effects from the multiLayered background. The Calderon projector is derived based on the general source-field relationship and the extinction theorem for inhomogeneous environment in electromagnetic theory. The Calderon identities can be naturally deduced based on this projector, which is then leveraged to precondition the EFIE with Layered kernel. An alternative implementation is then proposed to make the implementation of the preconditioner as efficient as the one in free space. Different numerical examples are designed to show the performance of the preconditioner, where the objects are located in different positions with respect to the Layered Medium, or different types of excitation are adopted. It is shown that the proposed effective and robust preconditioner makes the EFIE system converge rapidly in all cases, independent of the discretization density.
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Calderón preconditioned PMCHWT equation for Layered Medium problems
2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Weng Cho ChewAbstract:Electromagnetic scattering by dielectric objects in the presence of a Layered Medium is investigated by applying the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) equation combined with the Layered Medium Green's function. Due to the electric field integral equation (EFIE) operator involved, the spectrum of the PMCHWT equation is also undesired. When the surface is densely discretized, the condition of the resulting matrix is extremely bad. An effective Calder´ on preconditioner is developed in this paper to improve the convergence. Different from its free space counterpart, the Calder´ on identities for inhomogeneous Medium need to be re-derived. It is shown from numerical examples that the convergence of the PMCHWT system in Layered Medium can be significantly improved by using the proposed Calder´ on preconditioner.
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Calderón Preconditioned PMCHWT Equations for Analyzing Penetrable Objects in Layered Medium
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Weng Cho ChewAbstract:We study Calderon preconditioners for analyzing electromagnetic scattering by penetrable objects in a Layered Medium. To account for the scattering effects of the multiLayered background, the Layered Medium Green's function is adopted in the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) method. However, similar to the free-space case, the spectrum of the resulting equation is undesirable. This leads to a slow convergence of an iterative solver, especially when the geometry is densely meshed. To improve the convergence, a highly effective preconditioner is proposed. Different from its free-space counterpart, the preconditioning operator is constructed based on the Calderon identities for inhomogeneous Medium. To reduce the relatively high construction cost of the preconditioning operator, several alternative simplified schemes are proposed and analyzed. Finally, the performances of different preconditioners are examined and compared carefully through different numerical examples. It is shown that the convergence of the PMCHWT system in a Layered Medium can be significantly improved by using the proposed Calderon preconditioners.
Li Jun Jiang - One of the best experts on this subject based on the ideXlab platform.
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a calderon preconditioner for the electric field integral equation with Layered Medium green s function
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Weng Cho ChewAbstract:A Calderon preconditioner is developed for the analysis of electromagnetic scattering of perfect electrically conducting (PEC) objects embedded in a Layered Medium. The electric field integral equation (EFIE) is formulated with the kernel of Layered Medium Green's function to account for the effects from the multiLayered background. The Calderon projector is derived based on the general source-field relationship and the extinction theorem for inhomogeneous environment in electromagnetic theory. The Calderon identities can be naturally deduced based on this projector, which is then leveraged to precondition the EFIE with Layered kernel. An alternative implementation is then proposed to make the implementation of the preconditioner as efficient as the one in free space. Different numerical examples are designed to show the performance of the preconditioner, where the objects are located in different positions with respect to the Layered Medium, or different types of excitation are adopted. It is shown that the proposed effective and robust preconditioner makes the EFIE system converge rapidly in all cases, independent of the discretization density.
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Calderón preconditioned PMCHWT equation for Layered Medium problems
2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Weng Cho ChewAbstract:Electromagnetic scattering by dielectric objects in the presence of a Layered Medium is investigated by applying the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) equation combined with the Layered Medium Green's function. Due to the electric field integral equation (EFIE) operator involved, the spectrum of the PMCHWT equation is also undesired. When the surface is densely discretized, the condition of the resulting matrix is extremely bad. An effective Calder´ on preconditioner is developed in this paper to improve the convergence. Different from its free space counterpart, the Calder´ on identities for inhomogeneous Medium need to be re-derived. It is shown from numerical examples that the convergence of the PMCHWT system in Layered Medium can be significantly improved by using the proposed Calder´ on preconditioner.
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Calderón Preconditioned PMCHWT Equations for Analyzing Penetrable Objects in Layered Medium
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Weng Cho ChewAbstract:We study Calderon preconditioners for analyzing electromagnetic scattering by penetrable objects in a Layered Medium. To account for the scattering effects of the multiLayered background, the Layered Medium Green's function is adopted in the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) method. However, similar to the free-space case, the spectrum of the resulting equation is undesirable. This leads to a slow convergence of an iterative solver, especially when the geometry is densely meshed. To improve the convergence, a highly effective preconditioner is proposed. Different from its free-space counterpart, the preconditioning operator is constructed based on the Calderon identities for inhomogeneous Medium. To reduce the relatively high construction cost of the preconditioning operator, several alternative simplified schemes are proposed and analyzed. Finally, the performances of different preconditioners are examined and compared carefully through different numerical examples. It is shown that the convergence of the PMCHWT system in a Layered Medium can be significantly improved by using the proposed Calderon preconditioners.
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Analysis of scattering by PEC objects in Layered Medium with Calderón preconditioner
2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), 2014Co-Authors: Yongpin Chen, Li Jun Jiang, Sheng Sun, Min Meng, Weng Cho ChewAbstract:Electromagnetic scattering by perfect electrically conducting (PEC) objects in a Layered Medium is studied in this paper. The Layered Medium Green’s function is adopted as the kernel of the electric field integral equation (EFIE) so that the effects from the multiLayered background can be accounted for automatically. However, the spectrum of the EFIE with this kernel, is unfortunately undesirable. This leads to slow convergence of the iterative solution. To improve the convergence, the Calderon identities are derived and leveraged to precondition the EFIE. By utilizing Buffa-Christiansen (BC) basis function in discretizing the preconditioning operator, the preconditioner can be made completely multiplicative. Different numerical examples are designed to show the performance of the preconditioner. It is shown that the proposed preconditioner makes the EFIE system with Layered kernel converge rapidly, independent of the discretization density.
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a new green s function formulation for modeling homogeneous objects in Layered Medium
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Yongpin Chen, Weng Cho Chew, Li Jun JiangAbstract:A new Green's function formulation is developed systematically for modeling general homogeneous (dielectric or magnetic) objects in a Layered Medium. The dyadic form of the Green's function is first derived based on the pilot vector potential approach. The matrix representation in the moment method implementation is then derived by applying integration by parts and vector identities. The line integral issue in the matrix representation is investigated, based on the continuity property of the propagation factor and the consistency of the primary term and the secondary term. The extinction theorem is then revisited in the inhomogeneous background and a surface integral equation for general homogeneous objects is set up. Different from the popular mixed potential integral equation formulation, this method avoids the artificial definition of scalar potential. The singularity of the matrix representation of the Green's function can be made as weak as possible. Several numerical results are demonstrated to validate the formulation developed in this paper. Finally, the duality principle of the Layered Medium Green's function is discussed in the appendix to make the formulation succinct.
I. M. Fuks - One of the best experts on this subject based on the ideXlab platform.
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Wave diffraction by a rough boundary of an arbitrary plane-Layered Medium
IEEE Transactions on Antennas and Propagation, 2001Co-Authors: I. M. FuksAbstract:The problem of electromagnetic (EM) wave scattering by a slightly rough boundary of an arbitrary, Layered Medium is solved by a small perturdation method, The bistatic amplitude of scattering as well as scattering cross sections for statistically rough surface are calculated for linear and circular polarized waves. Along with the scattering into the upgoing waves in the homogeneous Medium, the scattering cross sections in the downgoing waves into a Layered Medium are obtained, Analytical results are applied to the modeling of natural, Layered media (ice and sand layers) remote sensing problems employing global position system (GPS) technics.
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Wave diffraction by rough interfaces in an arbitrary plane-Layered Medium
Waves in Random Media, 2000Co-Authors: I. M. Fuks, Alexander G VoronovichAbstract:Abstract The problem of electromagnetic wave scattering by a slightly rough interface in an arbitrarily Layered Medium is solved by a small-perturbation method. The bistatic amplitude of scattering as well as the scattering cross sections for statistically rough surfaces are calculated for linear polarized waves. Along with scattering into up-going waves in a homogeneous Medium and scattering cross sections in down-going waves into a Layered Medium, scattering amplitudes from a rough interface in the arbitrarily Layered Medium are obtained.
Y.v. Tarasov - One of the best experts on this subject based on the ideXlab platform.
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Localization of the field of a point source in a randomly Layered Medium
IEEE Transactions on Antennas and Propagation, 1991Co-Authors: V.d. Freylikher, Y.v. TarasovAbstract:The resonance approximation method, which permits calculation of the frequency correlators of fields propagating in randomly Layered media, is presented. It is used to find the coherent component, the intensity, and the energy flux of radiation of a point source in an infinite randomly Layered Medium. It is demonstrated that such a Medium acts as a fluctuation waveguide. >
