• Title/Summary/Keyword: FDTD

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Analysis of Stability Condition and Wideband Characteristics of 3D Isotropic Dispersion(ID)-FDTD Algorithm (3차원 ID-FDTD 알고리즘의 Stability Condition과 광대역 특성 분석)

  • Kim, Woo-Tae;Koh, Il-Suek;Yook, Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.4
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    • pp.407-415
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    • 2011
  • The stability condition and wideband characteristics of 3D ID-FDTD algorithm which has low dispersion error with isotropic dispersion are presented in this paper. 3D ID-FDTD method was proposed to improve the defect of the Yee FDTD such as the anisotropy and large dispersion error. The published paper calculated the stability condition of 3D ID-FDTD algorithm by using numerical method, however, it is thought that the examples were not sufficient to verify the stability condition. Thus, in this paper, various simulations are included in order to hold reliability under the conditions that the plane wave propagation is assumed with a single frequency and a wideband frequency. Also, the 3D ID-FDTD algorithm is compared to those that have the similar FDTD algorithm with ID-FDTD such as Forgy's method and non-standard FDTD method in a wideband. Finally, the radar cross section(RCS) for the large sphere with high dielectric constant is calculated.

2D Crank-Nicolson FDTD Method Based on Isotropic-Dispersion Finite Difference Equation for Lossy Media (손실 매질에 대한 Isotropic-Dispersion 유한 차분식의 2D Crank-Nicolson FDTD 기법)

  • Kim, Hyun;Koh, Il-Suek;Yook, Jong-Gwan
    • 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.

A Study of the Numerical Characteristics of the Envelope ADI-FDTD (Envelope ADI-FDTD의 수치적 특성에 관한 연구)

  • 주세훈;정경영;김형훈;김형동
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.6
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    • pp.584-590
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    • 2003
  • In this paper, the numerical characteristics of the recently developed Envelope ADI-FDTD are investigated. Through numerical simulations, it is shown that the unconditional stability of the Envelope ADI-FDTD is independent of time step size and we can get better dispersion accuracy than the traditional ADI-FDTD by analyzing the envelope of the signal. This fact gives the opportunity for extending the temporal step size to the Nyquist limit in certain cases. Numerical results show that the Envelope ADI-FDTD can be used as an efficient electromagnetic analysis tool especially in the single frequency or band limited systems.

Numerical Dispersion Relation for the 2-D ADI-FDTD Method (2-D ADI-FDTD의 수치적 분산특성에 관한 연구)

  • 주세훈;김형동
    • 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.

Analysis of Cutoff Frequencies of TEM Cell using FDTD (FDTD를 이용한 TEM Cell의 차단주파수에 관한 분석)

  • 윤영설;공순철;윤재훈;김정기
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.1
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    • pp.63-69
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    • 1999
  • In this paper, we analyze the cutoff frequencies of the TEM Cells by the FDTD, and introduce new boundary condition for the FDTD to identify the modes. Then, we confirm efficiency of the FDTD comparing results in previous papers. We also give our opinion from the results by FDTD to the arguments, which is resulted from different results about cutoff frequencies in the TEM Cells, especially the symmetric TEM Cells.

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Construction of a CPU Cluster and Implementation of a 3-D Domain Decomposition Parallel FDTD Algorithm (CPU 클러스터 구축 및 3차원 공간분할 병렬 FDTD 알고리즘 구현)

  • Park, Sungmin;Chu, Kwang-Uk;Ju, Saehoon;Park, Yoon-Mi;Kim, Ki-Baek;Jung, Kyung-Young
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.3
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    • pp.357-364
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    • 2014
  • In this work, we construct a CPU cluster to implement a parallel finite-difference time domain(FDTD) algorithm for fast electromagnetic analyses. This parallel FDTD algorithm can reduce the computational time significantly and also analyze electrically larger structures, compared to a single FDTD counterpart. The parallel FDTD algorithm needs communication between neighboring processors, which is performed by the MPI(Message Passing Interface) library and a 3-D domain decomposition is employed to decrease the communication time between neighboring processors. Compared to a single-processor FDTD, the speed up factor of a-CPU-cluster-based parallel FDTD algorithm is investigated for the normal mode and the hypermode and finally analyze an electrically large concrete structure by the developed parallel algorithm.

The improved FDTD algorithm for modeling of a smooth cured surface (완만한 곡면의 마들링을 위한 개선된 FDTD 앨거리즘)

  • 길병수;이상설
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.143-146
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    • 1999
  • The traditional FDTD method in the stair case, the CP-FDTD method, the modified CP-FDTD method, and Dey method have been developed to analyze smooth-curved- surface structures. These methods have some disadvantages such as inaccuracy of the stair-case FDTD, instability of the modified CP-FDTD, and complexity of Dey method. The improved algorithm presented here is a mixed-form of the modified CP algorithm and Dey algorithm. It is to avoid collinear borrowing approximations and to manipulate field update equations. All of preceding methods are applied to the E-plane sectoral horn antenna to get far-field patterns. The validity and applicability of the presented one is to be shown by comparing computed far-field patterns with measured values.

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Analysis of a Suspended Stripline using FDTD Method and Design of Suspended Stripline Filter (유한차분 시간영역법을 이용한 Suspended Stripline 해석 및 필터 설계)

  • 남윤권;박동철
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.6
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    • pp.605-611
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    • 2002
  • A simple and efficient analysis method of the suspended stripline using the finite-difference time-domain (FDTD) method is presented. New FDTD equations are derived using the contour path FDTD concept for the Yee cell which contains a dielectric sheet. The characteristic impedance and the effective dielectric constant of the suspended stripline are calculated using our proposed FDTD method. Using the calculated results, a 5-element lowpass filter is designed and fabricated. Our proposed FDTD method is validated by the measured data of the fabricated lowpass filter.

A Simple Method to Reduce the Splitting Error in the LOD-FDTD Method

  • Kong, Ki-Bok;Jeong, Myung-Hun;Lee, Hyung-Soo;Park, Seong-Ook
    • Journal of electromagnetic engineering and science
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    • v.9 no.1
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    • pp.12-16
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    • 2009
  • This paper presents a new iterative locally one-dimensional [mite-difference time-domain(LOD-FDTD) method that has a simpler formula than the original iterative LOD-FDTD formula[l]. There are fewer arithmetic operations than in the original LOD-FDTD scheme. This leads to a reduction of CPU time compared to the original LOD-FDTD method while the new method exhibits the same numerical accuracy as the iterative ADI-FDTD scheme. The number of arithmetic operations shows that the efficiency of this method has been improved approximately 20 % over the original iterative LOD-FDTD method.

Optimization of Extremely Low Numerical-Dispersion FDTD Method Based on H(2,4) Scheme for Wideband Analysis of Lossy Dielectric (H(2,4) 기법을 기반으로 한 저분산 FDTD 기법의 손실 매질의 광대역 해석을 위한 최적화 방법)

  • Oh, Ilyoung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.29 no.3
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    • pp.225-232
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    • 2018
  • This paper proposed the optimization method of the extremely low numerical-dispersion finite-difference time-domain (ELND-FDTD) method based on the H(2,4) scheme for wideband and extremely accurate electromagnetic properties of lossy material, which has a constant conductivity and relative permittivity. The optimized values of three variables are calculated for the minimum numerical dispersion errors of the proposed FDTD method. The excellent accuracy of the proposed method is verified by comparing the calculated results of three different FDTD methods and the analytical results of the two-dimensional dielectric cylinder scattering problem.