• Title/Summary/Keyword: FDTD method

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Design Analysis of GPS Satellite Receiver Antenna using FDTD Method (FDTD법을 이용한 GPS 위성 수신 안테나의 설계 해석)

  • 최희주;진태훈
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.145-148
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    • 1998
  • In this paper, a microstrip antenna is designed using a rectangular patch. To find characteristics of the antenna, computer simulations of the rectangular single microstrip patch antenna are performed with changing width. And we compared the result of computer simulation with the experimental value. Through the results, we found that the 3-D FDTD method is an effective method for designing microstrip patch antenna. According to simulation the resonant point has been found it in the frequency received from GPS satellite. It is thought that make it match by adjusting the feedpoint.

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The Three-Dimensional Acoustic Field Analysis using the Type C CIP Method (C형 CIP법을 이용한 3차원 음장해석)

  • Lee, Chai-Bong;Oh, Sung-Qwan
    • The Journal of the Korea institute of electronic communication sciences
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    • v.5 no.2
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    • pp.125-132
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    • 2010
  • The authors have investigated the acoustic field analysis using the Constrained Interpolation Profile(CIP) Method recently proposed by Yabe. This study has examined the calculation accuracy of the three-dimensional(3-D) acoustic field analysis using the type C CIP method. In this paper we show phase error of type C CIP method and the dependence on the wave-propagation direction in the type C CIP acoustic field analysis, and then demonstrate that it gives less-diffusive results than conventional analysis. Moreover, in comparison between type C-1 CIP, type C-2 CIP, type M CIP and FDTD, reports the memory requirements and calculation time of each method.

Analysis of Coaxial Line Transmission Charactristics and Shielding Effectiveness Using by Finite Difference Time Domain Method (시간영역 유한차분법을 이용한 동축선로의 전송특성 및 차폐효과 해석)

  • 남상식;윤현보;김정렬;백낙준;우종우
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.6 no.4
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    • pp.11-19
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    • 1995
  • In this paper, the Finite Difference Time Domain (FDTD) method is used to analyse the characteristics of the coaxial line transmission coefficent, shielding effectiveness, and compared to results of the moment method. The excitation mode of the Gaussian pulse is assumed to be a TEM-mode instead of the TE or TM-mode and in order to eliminate the reflected wave with in short length of the line. Calculated value of shielding effectiveness of the coaxial line by the FDTD are in good agreement with the results of the moment method.

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SAR Pattern of Biological Objects Contacted with Coaxial Waveguide Antenna Using the FDTD Method (유한 차분법을 이용한 동축 도파관 안테나에 접촉된 생체의 SAR 패턴에 관한 연구)

  • Koo, Sung-Mo;Lee, Chang-Won;Won, Chul-Ho;Cho, Jin-Ho
    • Journal of Biomedical Engineering Research
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    • v.18 no.3
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    • pp.261-266
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    • 1997
  • Nonevasive multifrequency microwave radiometry using coaxial waveguide antenna has been investigated for a homogeneous and four layer human body model. The coupling between coaxial waveguide antenna and a biological object was analyzed by use of the finite-difference time-domain(FDTD) method to obtain the absorbed power patterns in the media. The object studied in this paper was a homogeneous and four-layered lossy medium. The specific absorption rates(SAR) distribution which was corresponding to the temperature distribution was calculated in each region by use of the steady-state response in FDTD method. The SAR pattern of 1.2GHz was compared with that of 1.8GHz.

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FDTD 방법을 이용한 3T MRI용 RF 코일의 해석

  • 이종오;박준서;명노훈;박부식;김용권;정성택
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.6
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    • pp.976-983
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    • 2000
  • In this paper, Bridcage type RF coils used widely as RF coils for MRI and its applicable type, spiral type RF coil are analyzed and designed using FDTD method. In low tesla (IT, 1.5T) MRI system, several tools have been used for the analysis and design of the RF coils for MRI. This includes, so-called, LC equivalent circuit method for predicting the resonance frequency of the coil and the Biot-Savart law to determine the field distribution within the coil. Both of the circuit analysis and Biot-Savart law are low frequency techniques. Therefore, at high frequency applications, the circuit model approximation breaks down because the coil geometry is a significant fraction of the wavelength. In this paper, we analyzed and designed RF coils for 3T MRI using FDTD method. This method is a full wave analysis and very accurate at low and high frequencies. Also, this RF coils are actually fabricated and FDTD models of RF coils for MRI are proven.

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New Weighting Factor of 2D Isotropic-Dispersion Finite Difference Time Domain(ID-FDTD) Algorithm

  • Zhao, Meng;Koh, Il-Suek
    • 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.

Analysis of circular waveguide transformer using FDTD (원형 도파관 정합기의 FDTD에 의한 해석)

  • 이동국;홍재표
    • Journal of Korea Society of Industrial Information Systems
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    • v.8 no.1
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    • pp.9-17
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    • 2003
  • The finite-difference time-domain (FDTD) method is used to analyze circular waveguide transformer in order to match different two waveguides. 2-dimensional cylindrical FDTD algorithm is applied for rotationally symmetric. The transformer is inserted at a circular-to-circular waveguide junction and two type transformers are proposed. One is a partially dielectric filled circular waveguide type and the other is filled a tapered circular dielectric rod. The numerical results are derived for various structure parameters, such as transformer length. dielectric diameter and waveguide diameter.

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The radiation pattern calculation of the electromagnetically coupled microstrip dipole array antenna using the FDTD method (FDTD 방법을 이용한 전자기결합 마이크로스트립 다이폴 배열안테나의 복사패턴 계산)

  • 손영수;윤현보
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.7
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    • pp.1459-1467
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    • 1997
  • The current on the thin planar structure as an element of the transversely fed electromagnetically coupled(EMC) microstrip dipole array antenna is obtained by using the integral forms of the finite difference time domain(FDTD) method. This method was applied to calculating the optimum current distribution (Doplh-Tchebyscheff distribution) of each dipole element on the feed line as a function of their offset positions for the narrow main beam width and the side beam level below -20 dB. The current on each dipole substitutes for the electric and magnetic current densities on the virtual surface of the FDTD calculation to express the far field intensity, the calculation time and the computer memeory can be reduced to about 80% and 1.3 Mbyte, respectively. The calculated radiation patterns are compared to the measured values and these are in good agreement.

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FDTD Analysis of the Absorption Characteristics for Grid Ferrite Electromagnetic Wave Absorber (FDTD를 이용한 격자형 페라이트 전파흡수체 특성 해석)

  • 이재용;정연춘;명노훈
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.4
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    • pp.483-490
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    • 1998
  • The reflectivity of a grid ferrite electromagnetic wave absorber is analyzed using finite difference time domain (FDTD) method, which is usually used in anechoic chambers for EMI / EMS test. The frequency dispersive characteristics of ferrite medium and its boundary condition are modeled using magnetic flux in addition to E- and H-fields. By applying Floquets theorem, FDTD analysis of the grid ferrite absorber with periodic infinite array is simplified as a unit cell problem. The method of homogenization which is mainly utilized in the calculation of absorber reflectivity as a low frequency technique takes only into account volume fraction of the unit cell of the absorber except for the structure of medium geometry. However, the presented method in this paper can analyze the geometry effect of the unit cell with its medium characteristics up to high frequency region.

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Study for surface wave launcher of dielectric coated coaxial cable using FDTD method (FDTD 방법을 이용한 유전체를 입힌 동축 케이블의 표면파 로운처에 관한 연구)

  • 정진우;이창원김중표손현
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.173-176
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    • 1998
  • The surface wave launcher from the dielectric coated coaxial cable to dielectric slab is investigated. FDTD method using local subcell and contour-path model is applied to determine the fine geometrical features. The reflection coefficient in coaxial cable region is found using extract algorithm. In this paper, two structures are presented as coaxial slot surface wave launcher. One structure has a vertical launching angle, and the other has an arbitrary launching angle. The numerical results show that a certain launching angle is minimized the reflection coefficient.

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