An accurate and efficient finite element-boundary integral (FE-BI) method with graphics processing unit (GPU) acceleration is presented for solving electromagnetic problems with complex structures and materials. A mix...
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An accurate and efficient finite element-boundary integral (FE-BI) method with graphics processing unit (GPU) acceleration is presented for solving electromagnetic problems with complex structures and materials. A mixed testing scheme, in which the Rao-Wilton-Glisson and the Buffa-Christiansen functions are both employed as the testing functions, is first presented to improve the accuracy of the FE-BI method. An efficient absorbing boundary condition (ABC)-based preconditioner is then proposed to accelerate the convergence of the iterative solution. To further improve the efficiency of the total computation, a GPU-accelerated multilevel fast multipole algorithm (MLFMA) is applied to the iterative solution. The radar cross sections (RCS) of several benchmark objects are calculated to demonstrate the numerical accuracy of the solution and also to show that the proposed method not only is free of interior resonance corruption, but also has a better convergence than the conventional FE-BI methods. The capability and efficiency of the proposed method are analyzed through several numerical examples, including a large dielectric coated sphere, a partial human body, and a coated missile-like object. Compared with the 8-threaded CPU-based algorithm, the GPU-accelerated FE-BI-MLFMA algorithm can achieve a total speedup up to 25.5 times.
In recent years, the characteristic basis function method has been developed as an efficient approach for the solution of large electromagnetic radiation or scattering problems. According to this technique, the curren...
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In recent years, the characteristic basis function method has been developed as an efficient approach for the solution of large electromagnetic radiation or scattering problems. According to this technique, the currents over the scenario under analysis are defined using a set of pre-computed characteristic basis functions, associated with a number of blocks into which the geometry is partitioned. This involves some computational advantages due to the reduction of the number of unknowns compared to conventional approaches. However, additional pre-processing time is introduced due to the computation of the CBFs and the reduced coupling matrix. A novel strategy is presented in this study in order to accelerate the generation of the reduced matrix, based on the application of the multilevel fast multipole algorithm.
We consider electromagnetics problems involving composite geometries with coexisting open and closed conductors. Hybrid integral equations are presented to improve the efficiency of the solutions, compared to the conv...
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We consider electromagnetics problems involving composite geometries with coexisting open and closed conductors. Hybrid integral equations are presented to improve the efficiency of the solutions, compared to the conventional electric-field integral equation. We investigate the convergence characteristics of iterative solutions of large composite problems with the multilevel fast multipole algorithm. Following a thorough study of how the convergence characteristics depends on the problem geometry, formulation, and iterative solvers, we provide concrete guidelines for efficient solutions.
The electromagnetic (EM) scattering characteristics of target above coastal environment are complicated due to the simultaneous existence of ground region and sea region. Nevertheless, the actual target possesses both...
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The electromagnetic (EM) scattering characteristics of target above coastal environment are complicated due to the simultaneous existence of ground region and sea region. Nevertheless, the actual target possesses both conducting part and dielectric part. Such a composite scattering problem involves multiple media parameters and large amount of unknowns. Hence, aiming at accurately and efficiently calculating the EM scattering from combined conducting and dielectric target above coastal environment, the hybrid SIE-KA method is introduced in which single integral equation (SIE) method is utilized to reduce the number of combined target's unknowns and Kirchhoff approximation (KA) is applied to obtain induced electric and magnetic current on the surface of coastal environment. Moreover, multilevel fast multipole algorithm (MLFMA) is adopted to significantly reduce the computational cost and memory requirement. Several numerical examples demonstrate the accuracy and efficiency of the hybrid method. Finally, the EM scattering characteristics of combined conducting and dielectric target above coastal environment have been studied. The radar cross section (RCS) curves with different category of environment, polarization mode, working frequency, statistic parameters of coastal environment, permittivity of target's dielectric part, target's height and target category have been analyzed in detail to provide some useful conclusions. The approach and results can be broadly applied in remote sensing simulation of coastal environment with combined target.
The hybrid volume-surface integral equation (VSIE) method has the advantage of solving electromagnetic scattering problems involving complex structure mixed metal with dielectric. In this paper, a method combining VSI...
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The hybrid volume-surface integral equation (VSIE) method has the advantage of solving electromagnetic scattering problems involving complex structure mixed metal with dielectric. In this paper, a method combining VSIE with overlapped domain decomposition method (ODDM) is used to analyze electromagnetic scattering problems successfully. To further improve efficiency, the multilevel fast multipole algorithm (MLFMA) is adopted, then a novel VSIE-ODDM-MLFMA is proposed. Numerical results show that the proposed method has low memory requirement, fast convergence, and accurate simulation result. It indicates that the proposed method has the ability to analyze complicated electromagnetic problems.
In solving systems of linear equations arising from practical scientific and engineering modelling and simulations such as electromagnetics applications, it is important to choose a fast and robust solver. Due to the ...
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In solving systems of linear equations arising from practical scientific and engineering modelling and simulations such as electromagnetics applications, it is important to choose a fast and robust solver. Due to the large scale of those problems, preconditioned Krylov subspace methods are most suitable. In electromagnetics simulations, the use of preconditioned Krylov subspace methods in the context of multilevel fast multipole algorithms (MLFMA) is particularly attractive. In this paper, we present a short survey of a few preconditioning techniques in this application. We also compare several preconditioning techniques combined with the Krylov subspace methods to solve large dense linear systems arising from electromagnetic scattering problems and present some numerical results.
For 3d waveguiding system calculations we used the Electric Field Integral Equation (EFIE) model, applied to infinitely thin, perfectly conducting waveguide surfaces. The solution represents induced current, from whic...
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For 3d waveguiding system calculations we used the Electric Field Integral Equation (EFIE) model, applied to infinitely thin, perfectly conducting waveguide surfaces. The solution represents induced current, from which the field in the device is obtained. With the help of this method an asymmetric mode converter TE01-TE11 was simulated and optimized for maximum efficiency. We have also studied a helically corrugated structure, which is used in pulse compressors, and analyzed the structures dispersion curves and compared it with measurement results.
An efficient two-level preconditioning technique based on sparse recursive Cholesky factorization (SRCF) is proposed to solve linear equations in monostatic radar cross section *** SRCF preconditioner is used as the f...
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An efficient two-level preconditioning technique based on sparse recursive Cholesky factorization (SRCF) is proposed to solve linear equations in monostatic radar cross section *** SRCF preconditioner is used as the first level preconditioning, and a spectral preconditioner, constructed from the eigenvectors of the SRCF preconditioned system, is adopted as the second level preconditioning. The resultant linear systems are solved by restarted generalized minimal residual method. multilevel fast multipole algorithm is implemented to accelerate computation and reduce memory requirement. Numerical results demonstrate the proposed method is efficient in reducing the number of matrix-vector product, and speed-up factors of 4.26 and 5.89 are observed for electromagnetic scattering by a perfect electric conductor almond and a civil aircraft model, respectively. (C) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:14831488, 2012;View this article online at ***. DOI 10.1002/mop.26823
Domain decomposition methods are efficient for analyzing scattering problems with large-scale structures. In the present paper, an improved combination of Overlapped Domain Decomposition Method of Integral Equations (...
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Domain decomposition methods are efficient for analyzing scattering problems with large-scale structures. In the present paper, an improved combination of Overlapped Domain Decomposition Method of Integral Equations (IE-ODDM) and multilevelfast Multi-pole algorithm (MLFMA) is developed. Amount of independent MLFMA progresses of sub-domains are departed and re-integrated, such that the total CPU time of coupled effects in IE-ODDM can be saved. The proposed method developed minimal-completed sub-trees of sub-domains to reduce redundant aggregations of the MLFMA process blended in IE-ODDM. Numerical results and comparisons with the original method are provided, which suggest that the proposed combination integrates MLFMA with IE-ODDM better than the original combined method, and it can greatly improve the computational efficiency of coupled effects in IE-ODDM.
A novel and general method for a fast calculation of scattering/radiation fields is proposed by expressing the source-field relationship through the method of moments (MoM). The scattering fields in the observation re...
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A novel and general method for a fast calculation of scattering/radiation fields is proposed by expressing the source-field relationship through the method of moments (MoM). The scattering fields in the observation region are expanded by a set of SWGs defined on an auxiliary mesh. The associated expansion coefficients are obtained from matrix vector multiplication (MVM) of the impedance matrix in the MoM and the equivalent currents. The proposed method can enable an accurate near-field calculation without a special treatment of the singularity. Numerical experiments on targets with complex configurations are conducted to validate the performance of the proposed method.
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