No description available.

The Fast Multipole Method (FMM) allows for rapid evaluation of the fundamental solution of the Helmholtz equation, known as Green's function. Evaluation times are reduced from O(N^2), using the direct approach, down to O(N log N), with an accuracy specified by the user. The Helmholtz equation, and variations thereof, including the Laplace and wave equations, are used to describe physical phenomena in electromagnetics, acoustics, heat dissipation, and many other applications. This thesis studies the acceleration of the low-frequency FMM, where the product of the wave number and the translation distance of expansion coefficients is relatively low. A general-purpose graphics processing unit (GPGPU), with native support of double-precision arithmetic, was used in the implementation of the LF FMM, with a resulting speedup of 4-22X over a conventional central processing unit (CPU), running in a single-threaded manner, for various simulations involving hundreds of thousands to millions of sources.

The Fast Multipole Method (FMM) allows for rapid evaluation of the fundamental solution of the Helmholtz equation, known as Green's function. Evaluation times are reduced from O(N^2), using the direct approach, down to O(N log N), with an accuracy specified by the user. The Helmholtz equation, and variations thereof, including the Laplace and wave equations, are used to describe physical phenomena in electromagnetics, acoustics, heat dissipation, and many other applications. This thesis studies the acceleration of the low-frequency FMM, where the product of the wave number and the translation distance of expansion coefficients is relatively low. A general-purpose graphics processing unit (GPGPU), with native support of double-precision arithmetic, was used in the implementation of the LF FMM, with a resulting speedup of 4-22X over a conventional central processing unit (CPU), running in a single-threaded manner, for various simulations involving hundreds of thousands to millions of sources.

No description available.

Electromagnetic scattering by 3-D arbitrarily shaped homogeneous dielectric objects is characterized. In the analysis, the method of moments is first employed to solve the combined field integral equation for scattering properties of these three-dimensional homogeneous dielectric objects of arbitrary shape. The fast multipole method, and the multi-level fast multipole algorithm are implemented into our codes for matrix-vector manipulations. Specifically, four proposals are made and discussed to increase convergence and accuracy of iterative procedures (conjugate gradient method). Numerical results are obtained using various methods and compared to each other. / Singapore-MIT Alliance (SMA)

This thesis presents an improved method for dynamic force computation applicable to both electrostatic and electromagnetic conductors with complex 3D geometries. During the transient simulation of electrostatic actuated MEMS, the positions of the conductors as well as the potential applied to the conductors may change, necessitating recalculation of electrostatic forces at each time step of computation. Similarly, during the simulation of electromagnetic actuated MEMS, the current re-distribution in the conductors requires recalculation of electromagnetic forces at each time step. In this thesis, a simple method based on the principles of fast multipole algorithm is explored to effectively recalculate the potential coefficients to compute the surface charges and thereby forces during transient simulation of electrostatic conductors. The proposed method improves the speed of electrostatic force computation by 15 - 60% at each time step, depending on the displacement, with an error less than 3%. Electromagnetic forces are also computed by the same method. In addition, an efficient method is also presented for electrostatic analysis of dummy metal filled interconnects.

No description available.

Tree-based methods have wide applications for solving large-scale problems in electromagnetics, astrophysics, quantum chemistry, fluid mechanics, acoustics, and many more areas. This thesis focuses on their applicability for solving large-scale problems in electromagnetics. The Barnes-Hut (BH) algorithm and the Fast Multipole Method (FMM) are introduced along with a survey of important previous work. The required theory for applying those methods to problems in electromagnetics is presented with particular emphasis on the capacitance extraction problem and broadband full-wave scattering. A novel single source approximation is introduced for approximating clusters of electrostatic sources in multi-layered media. The approximation is derived by matching the spectra of the field in the vicinity of the stationary phase point. Combined with the BH algorithm, a new algorithm is shown to be an efficient method for evaluating electrostatic fields in multilayered media. Specifically, the new BH algorithm is well suited for fast capacitance extraction. The BH algorithm is also adapted to the scalar Helmholtz kernel by using the same methodology to derive an accurate single source approximation. The result is a fast algorithm that is suitable for accelerating the solution of the Electric Field Integral Equation (EFIE) for electrically small structures. Finally, a new version of FMM is presented that is stable and efficient from the low frequency regime to mid-range frequencies. By applying analytical derivatives to the field expansions at the observation points, the proposed method can rapidly evaluate vectorial kernels that arise in the FMM-accelerated solution of EFIE, the Magnetic Field Integral Equation (MFIE), and the Combined Field Integral Equation (CFIE).

Tree-based methods have wide applications for solving large-scale problems in electromagnetics, astrophysics, quantum chemistry, fluid mechanics, acoustics, and many more areas. This thesis focuses on their applicability for solving large-scale problems in electromagnetics. The Barnes-Hut (BH) algorithm and the Fast Multipole Method (FMM) are introduced along with a survey of important previous work. The required theory for applying those methods to problems in electromagnetics is presented with particular emphasis on the capacitance extraction problem and broadband full-wave scattering. A novel single source approximation is introduced for approximating clusters of electrostatic sources in multi-layered media. The approximation is derived by matching the spectra of the field in the vicinity of the stationary phase point. Combined with the BH algorithm, a new algorithm is shown to be an efficient method for evaluating electrostatic fields in multilayered media. Specifically, the new BH algorithm is well suited for fast capacitance extraction. The BH algorithm is also adapted to the scalar Helmholtz kernel by using the same methodology to derive an accurate single source approximation. The result is a fast algorithm that is suitable for accelerating the solution of the Electric Field Integral Equation (EFIE) for electrically small structures. Finally, a new version of FMM is presented that is stable and efficient from the low frequency regime to mid-range frequencies. By applying analytical derivatives to the field expansions at the observation points, the proposed method can rapidly evaluate vectorial kernels that arise in the FMM-accelerated solution of EFIE, the Magnetic Field Integral Equation (MFIE), and the Combined Field Integral Equation (CFIE).

京都大学 / 新制・課程博士 / 博士(理学) / 甲第22991号 / 理博第4668号 / 新制||理||1670(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 柳瀬 陽一, 教授 川上 則雄, 教授 石田 憲二 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM