• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.191-198
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• 2011

In this paper, a method to approximate a multi-layer Green's function is proposed based on a FDTD scheme and a rational function approximation. For a given horizontal propagation wavenumber, time domain response is calculated and then Fourier transformed to the spectral domain Green's function. Using the rational function approximation, the pole and residue of the Green's function can be estimated, which are crucial for a calculation of a path loss. The proposed method can provide a wideband Green's function, while the conventional normal mode method can be applied to a single frequency problem. To validate the proposed method, We consider two problems, one of which has a analytical solution. The other is about multi-layer case, for which the proposed method is compared with the known normal mode solution, Kraken.

• The Journal of the Korea Contents Association
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• v.7 no.2
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• pp.125-131
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• 2007

An iterative Green's function method (IGFM) is introduced in order to analyze complex electromagnetic waveguide stub structures in view of a university student. The IGFM utilizes a Green's function approach and an regional iteration scheme. A physical iteration mechanism with simple mathematical equations facilitates clear formulations of the IGFM. Scattering characteristics of a standard E-plane T-junction stub in a parallel-plate waveguide are theoretically investigated in terms of the IGFM. Numerical computations illustrate the characteristics of reflection and transmission powers versus frequency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.1001-1010
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• 2001

In TLM method, Discrete Green's function ABC have been used when improved the exactness of analyzing in wide frequency band. But this technology has a complicated process to apply absorbing boundary, which means it needs additional numerical analyzing process to obtain discrete Green's function data. so, In this paper, we propose new Green's absorbing layer for simple process to apply absorbing boundary. newly proposed Green's absorbing layer is produced by applying of loss operation, loading discrete Green's function with attenuation. A state of optimum absorbing would be obtained by relation between increasing rate of loss, attenuation constant and length of green's absorbing layer. and then Analysts of waveguide BPF is carried out using Green's absorbing layer within state of optimum absorbing, then this result is in corrective agreement with the result applying traditional discrete Green's function ABC.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.6 s.324
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• pp.79-86
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• 2004

In the integration of Sommerfeld type for space domain Green's function, a accurate closed-from Green's function method provides more exact solution than the typical complex image method and two-level method. The accurate closed-form Green's function method is applied to obtain the space domain Green's functions of planar structures with general sources. Please put the abstract of paper here.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.2
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• pp.77-85
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• 1998

Propagation of elastic surface waves in anisotropic media is considered in this study. An analytical technique is proposed to study the scattering of surface waves at the interface between two anisotropic quarter-spaces. The Green's function technique is used to derive a system of equations which can determine the scattering coefficients at the interface. A numerical study is carried out and the trade-offs between the material anisotropy and inhomogeneity are studied.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1122-1130
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• 2001

In this paper, by applying the spectral domain wavelet concept to Green function, a fast spectral domain calculation of scattered fields is proposed to get the solution for the radiation integral. The spectral domain wavelet transform to represent Green function is implemented equivalently in space via the constant-Q windowing technique. The radiation integral can be calculated efficiently in the spectral domain using the windowed Green function expanded by its eigen functions around the observation region. Finally, the same formulation as that of the conventional fast multipole method (FMM) is obtained through the windowed Green function and the spectral domain calculation of the radiation integral.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.3
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• pp.258-268
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• 2008

The radiation potential of a ship advancing in waves is studied using the 3D time-domain forward-speed free-surface Green function and the Green integral equation. Numerical solutions are obtained by making use of the 2nd order BEM(Boundary Element Method) which make it possible to take account of the line integral along the waterline in a rigorous manner. The 6 degree of freedom motion memory functions of a hemisphere and the Wigley seakeeping model obtained by direct integration of the time-domain 3D potentials over the wetted surface are presented for various Froude numbers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.219-222
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• 2007

The paper deals with the rigorous analysis of three layered media structures. The dyadic Green's function for three layer medium is derived. The Green's functions belonging to the kernel of the integral equation are expressed as Sommerfeld integrals, in which surface wave effects are automatically included. We propose this integral representation as the most appropriate in the spatial domain analysis of slive structure. Also, we used extraction method for the convergence of this integral function. Finally, some numerical results are presented. These computed value show good agreement with proposed this method.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.1
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• pp.1-9
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• 2004

In this study, several new types of floating breakwater are proposed according to the geometry of the vertical barrier and the existence of horizontal plate, and are compared to the steel floating breakwater adopted in Won-Jun fishing port and the performance of wave control is numerically investigated by using Green function method. From the numerical results, model attached the horizontal barrier under the vertical barrier is more efficient for reflection and transmission coefficient than the steel floating breakwater in Won-Jun fishing port. It is confirmed that the transmitted waves can be controlled efficiently by optimizing the length and distance of a vertical and horizontal barriers.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.403-405
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• 2003

An iterative Green's function method (IGFM) is introduced to analyze complex electromagnetic waveguide structures in view of the university student. The IGFM utilizes the Green's function and iteration scheme. The physical mechanism with simple mathematical equations is used to formulate the IGFM. Scattering characteristics of a standard E-plane T-junction in a parallel-plate waveguide are theoretically investigated in terms of the IGFM. Numerical computations illustrate the characteristics of resection and transmission powers versus frequency. A dominant-mode solution is presented and compared with the higher-mode solutions.