• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.5
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• pp.181-186
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• 2003

This paper presents a numerical dispersion relation for the two-dimensional finite-difference time-domain method based on the alternating-direction implicit time-marching scheme(2-D ADI-FDTD), which method has the potential to considerably reduce tile number of time iterations especially in case where the fine spatial lattice relative to the wavelength is used to resolve fine geometrical features. The proposed analytical relation for 2-D ADI-FDTD is compared with those relations in the Previous works. Through numerical tests, the dispersion equation of this work was shown as correct one for 2-D ADI-FDTD.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.10
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• pp.38-45
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• 2002

This paper presents the new Compact 2D ADI-FDTD(Alternating-Direction Implicit Finite-Difference Time-Domain) method, where the time step is no longer restricted by the numerical stability condition. This method is an accelerating algorithm for the conventional Compact 2D FDTD method. To validate this algorithm, we have analyzed the dispersion characteristics of the hollow rectangular waveguide and the shielded microstrip line. The results of the proposed method are very well agreed with those of both the conventional analytic method and the Compact 2D FDTD method. The CPU time for analysis of this method is very much reduced compared with the conventional Compact 2D FDTD method. The proposed method is valuable as a fast algorithm in the research of dispersion characteristics of the waveguide structures.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.582-591
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• 2000

In this paper, the Finite-Difference Time-Domain(FDTD) modeling method of the Korean human head is introduced to calculate electromagnetic energy absorption for the human head by mobile phones. After MRI scanning data is obtained, 2 dimensional(2D) segmentation is done from the 2D MRI image data by the semi-automatic method. Then, 3D dense segmentation data with $1mm\times1mm\times1mm$ is constructed from the 2D segmentation data. Using the 3D segmentation data, coarse FDTD models of human head that is tilted arbitrarily to model the condition of tilted usage of mobile phone.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1131-1138
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• 2001

This paper presents the new Compact 2D Haar-wavelet-based MultiResolution Time-Domain method (MRTD) as an accelerating algorithm for the conventional Compact BD Finite-Difference Time-Domain method (FDTD). To validate this algorithm, we analyzed the dispersion characteristics of the hollow rectangular waveguide and dielectric slab-loaded rectangular waveguide. The results of the proposed method are very weal agreed with those of both the conventional analytic method and the Compact 2D FDTD method. The CPU time for analysis of this method is reduced to about a half of the conventional Compact 2D FDTD method. The proposed method is valuable as a fast algorithm in the research of dispersion characteristics of waveguide structures.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.805-814
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• 2010

The Crank-Nicolson isotropic-dispersion finite difference time domain(CN ID-FDTD) scheme is proposed based on isotropic-dispersion finite difference(ID-FD) $equation^{[1],[2]}$. The dispersion relation of CN ID-FDTD is derived for lossy media by solving the eigenvalue problem of iteration matrix in spatial spectral domain, in addition, the weighting factors and scaling factors of the CN ID-FDTD scheme are presented for low dispersion error. The CN ID-FDTD scheme makes the dispersion error drastically reduced and shows accurate numerical results compared to the conventional Crank-Nicolson FDTD method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.67-69
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• 2012

In this paper, electromagnetic scattering analysis of Fresnel Lens by using 2D FDTD method was performed. Fresnel lens which is consigured 7 diffracted conductors, and considered at 5GHz. As a result, axial gain characteristic corresponding to near design focusing distance at 0.71m is 26dB.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.12
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• pp.1-10
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• 1999

In this paper, we analyzed the radiation patterns of a monopole antenna mounted on the complex structures by using FDTD method associated with 3-D PML absorbing boundary condition. In order to validate the proposed FDTD code, the radiation patterns of monopole antenna mounted on cylinders and spheres were compared with the exact solutions of $Carter^{[1]}$ and $Harrington^{[2]}$. For all case considered, the predicted radiation pattern exhibited excellent agreement with exact solution. To be able to model the more complex structures, the proposed FDTD methods are combined with BRL-CAD. And this procedures is applied to predict the radiation patterns of a wire antenna attached to the top of a Blackhawk helicopter.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.183-186
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• 2005

A two dimensional (2-D) finite-difference time-domain (FDTD) method based on a novel finite difference scheme is developed to eliminate the numerical dispersion errors. In this paper, numerical dispersion and stability analysis of the new scheme are given, which show that the proposed method is nearly dispersionless, and stable for a larger time step than the standard FDTD method.

• Journal of electromagnetic engineering and science
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• v.8 no.4
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• pp.139-143
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• 2008

In this paper, a new scheme to calculate the weighting factor of the 2-D isotropic-dispersion finite difference time domain(ID-FDTD) is proposed. The weighting factor in [1] was formulated in free space, so that it may not be optimal in dielectric media. Therefore, the weighting factor was reformulated by considering the material properties and using the least mean square method. As a result, a minimum numerical dispersion error for any dielectric media is guaranteed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.830-838
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• 2003

In this paper, TX/RX dual operation microstrip single antenna for satellite communication is designed, analyzed, fabricated and measured. TX/RX frequency ranges are 14.0∼l4.5 GHz, 11.7∼12.75 GHz in respectively and vertical and horizontal polarizations are used for TX and RX. This antenna uses microstrip direct feeding for RX and aperture coupled strip-line feeding for TX and accommodates stacked elements for a high directivity and wide impedance bandwidth. In an analysis of single element, FDTD and MOM was compared and FDTD analysis was more accurate because of the consideration of finite structure and imperfect two ground planes. The proposed structure facilitates generally to an extension of two dimensional array and lower an unwanted radiation by strip-line feed in TX. TX/RX 8${\times}$4 array has a return loss below -10 dB, -14 dB in TX, RX respectively and a gain ranging from 19.1∼20.7 dB in TX, 21.2∼21.8 dB in RX which has a radiation efficiency of 43∼5l %, 52∼57 %.