• Title/Summary/Keyword: FDTD simulation

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Effects of Antenna Modeling in 2-D FDTD Simulation of an Ultra-Wide Band Radar for Nondestructive Testing of a Concrete Wall (콘크리트 벽의 비파괴검사를 위한 초광대역 레이더의 2차원 FDTD 시뮬레이션에서 안테나 모델링의 영향)

  • Joo, Jeong-Myeong;Hong, Jin-Young;Shin, Sang-Jin;Kim, Dong-Hyeon;Oh, Yisok
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.1
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    • pp.98-105
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    • 2013
  • This paper presents a finite-difference time-domain(FDTD) simulation and a data processing technique for radar sensing of the internal structure of a wall using an ultra-wide band antenna. We first designed an ultra-wide band anti-podal vivaldi antenna with a frequency range of 0.3~7 GHz which is chosen to be relatively low after considering the characteristics of wave attenuation, wall penetration, and range resolution. In this study the two-dimensional FDTD technique was used to simulate a wall-penetration-radar experiment under practical conditions. The next, the measured radiation pattern of the practical antenna is considered as an equivalent source in the FDTD simulation, and the reflection data of a concrete wall and targets are obtained by using the simulation. Then, a data processing technique has been applied to the FDTD reflection data to get a radar image for remote sensing of the internal structure of the wall. We compared the two different source excitations in the FDTD simulation; (1) commonly-used isotropic point sources and (2) polynomial curve fitting sources of the measured radiation pattern. As a result, when we apply the measured antenna pattern into the FDTD simulation, we could obtain about 2.5 dB higher signal to noise level than using a plane wave incidence with isotropic sources.

Comparison of FDTD Simulation Results with Measurement Data of a Ground-Penetrating Radar (지하침투 레이더의 FDTD 모의계산 결과와 측정자료의 비교)

  • Hyun, Seung-Yeup;Kim, Se-Yun;Kim, Young-Sik
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.7
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    • pp.1-8
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    • 1999
  • A complete electromagnetic simulation for a ground-penetrating radar(GPR) is implemented by employing 3-dimensional dispersive finite-difference time-domain(FDTD) method. The presented simulation model includes the cavity-backed bow-tie antennas, which are terminated by resistors. And an equivalent cirvuit consisting of the input impedance of the antenna and the characteristic impedance of the feed line is used to calculate the response in the receiving antenna. Actual emasurements of a GPR system including our manufactured bow-tie antenna pair are performed just above dry sand contained in a PVC tank. It is confirmed that the FDTD simulation results agree well with the actual measurement data.

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Application of 3D ADI-FDTD Method for GPR System Simulation (GPR 시스템 시뮬레이션을 위한 3차원 ADI-FDTD 기법의 적용)

  • Jeon Won Sok;Yeo Woonsik;Yun Seung Hyun;Kim Hyeongdong
    • Proceedings of the IEEK Conference
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    • 2004.06a
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    • pp.131-134
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    • 2004
  • This paper has been studied a ADI-FDTD(Alternating Direction Implicit Finite Difference Time Domain ) algorithm using an alternating Direction time-stepping scheme for GPR( Ground-Penetrating Radar ) system simulation. We did the numerical formulations for three-dimensional ADI-FDTD algorithm and PML(Perfect Matched Layer), and made an simple experiment on a arbitrary cube with programed algorithms. And then we compared its computed results with those of conventional FDTD.

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Accurate Simulation of a Shallow-etched Grating Antenna on Silicon-on-insulator for Optical Phased Array Using Finite-difference Time-domain Methods

  • Seo, Dong-Ju;Ryu, Han-Youl
    • Current Optics and Photonics
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    • v.3 no.6
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    • pp.522-530
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    • 2019
  • We present simulation methods to accurately determine the transmission efficiency and far-field patterns (FFPs) of a shallow-etched waveguide grating antenna (WGA) formed on a silicon-on-insulator wafer based on the finite-difference time-domain (FDTD) approach. The directionality and the FFP of a WGA with >1-mm in length can be obtained reliably by simulating a truncated WGA structure using a three-dimensional FDTD method and a full-scale WGA using a two-dimensional FDTD with the effective index method. The developed FDTD methods are applied to the simulation of an optical phased array (OPA) composed of a uniformly spaced WGA array, and the steering-angle dependent transmission efficiency and FFPs are obtained in OPA structures having up to 128-channel WGAs.

A Simulation of the Detection of Buried Facilities using FDTD (FDTD를 이용한 매설 설비의 탐지 시뮬레이션)

  • Lee, Woo-Chan;Kim, Hyeong-Seok
    • Journal of The Institute of Information and Telecommunication Facilities Engineering
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    • v.10 no.2
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    • pp.68-73
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    • 2011
  • In Ground Penetrating Radar (GPR) for buried object detection, it is important to identify a buried target because removal of an unwanted target requires as much time and effort as does a wanted target. For a simulation of the target identification, the FDTD (Finite Difference Time Domain) and PML (Perfectly Matched Layer) techniques are widely used. Simulation results vary depending on the type of the buried object and the position of the source. As a result, this paper illustrates the range (time) profile of the five types of facilities including PEC (Perfect Electric Conductor) rectangular box and pipes, and shows the comparison of the range profile of the buried facilities.

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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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A new absorbing boundary condition for the FDTD simulation of waveguides (도파관 구조의 FDTD해석을 위한 새로운 흡수경계조건)

  • 박면주;남상욱
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.12
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    • pp.3227-3234
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    • 1996
  • This paper proposes a new absorbing boundary condition(ABC) for the FDTD simulation of waveguide problems. It is based on the exact analytic expression for the time domain EM wave propatation in the waveguide. The ABC derived from the expression has a convolution form whose kernel (the discrete Green's function) has a simple, closed form formula. Also, it is applicable to the wide variety of waveguide types with conducting boundaries and complex cross-sectional shapes.

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Implementation of Massive FDTD Simulation Computing Model Based on MPI Cluster for Semi-conductor Process (반도체 검증을 위한 MPI 기반 클러스터에서의 대용량 FDTD 시뮬레이션 연산환경 구축)

  • Lee, Seung-Il;Kim, Yeon-Il;Lee, Sang-Gil;Lee, Cheol-Hoon
    • The Journal of the Korea Contents Association
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    • v.15 no.9
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    • pp.21-28
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    • 2015
  • In the semi-conductor process, a simulation process is performed to detect defects by analyzing the behavior of the impurity through the physical quantity calculation of the inner element. In order to perform the simulation, Finite-Difference Time-Domain(FDTD) algorithm is used. The improvement of semiconductor which is composed of nanoscale elements, the size of simulation is getting bigger. Problems that a processor such as CPU or GPU cannot perform the simulation due to the massive size of matrix or a computer consist of multiple processors cannot handle a massive FDTD may come up. For those problems, studies are performed with parallel/distributed computing. However, in the past, only single type of processor was used. In GPU's case, it performs fast, but at the same time, it has limited memory. On the other hand, in CPU, it performs slower than that of GPU. To solve the problem, we implemented a computing model that can handle any FDTD simulation regardless of size on the cluster which consist of heterogeneous processors. We tested the simulation on processors using MPI libraries which is based on 'point to point' communication and verified that it operates correctly regardless of the number of node and type. Also, we analyzed the performance by measuring the total execution time and specific time for the simulation on each test.

An Alternating Implicit Block Overlapped FDTD (AIBO-FDTD) Method and Its Parallel Implementation

  • Pongpaibool, Pornanong;Kamo, Atsushi;Watanabe, Takayuki;Asai, Hideki
    • Proceedings of the IEEK Conference
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    • 2002.07a
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    • pp.137-140
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    • 2002
  • In this paper, a new algorithm for two-dimensional (2-D) finite-difference time-domain (FDTD) method is presented. By this new method, the maximum time step size can be increased over the Courant-Friedrich-Levy (CFL) condition restraint. This new algorithm is adapted from an Alternating-Direction Implicit FDTD (ADI-FDTD) method. However, unlike the ADI-FDTD algorithm. the alternation is performed with respect to the blocks of fields rather than with respect to each respective coordinate direction. Moreover. this method can be efficiently simulated with parallel computation. and it is more efficient than the conventional FDTD method in terms of CPU time. Numerical formulations are shown and simulation results are presented to demonstrate the effectiveness and efficiency of our proposed method.

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Design of Low Field RF Coil for Open MRI System by Electric Dipole Radiation

  • 김경락;양형진;오창현
    • Proceedings of the KSMRM Conference
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    • 2001.11a
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    • pp.174-174
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    • 2001
  • Purpose: Dimensions of body RF coil composed of 4 rectangular loops for low field open MRI hav been optimized. The design result shows the field inhomogeneity of B1 field below 1.5 dB in the 25 cm DSV can be achieved. Method: Our low field RF coil is composed of 4 rectangular strip loops that assumed to b located at both the bottom and top sides of permanent magnet. All the loops have identica dimensions and current amplitude. First, the inductance of a loop is calculated. Second, the current distribution on the coil strip is calculated by using finite difference time doma method (FDTD). It takes as much as 4 days in FDTD simulation for low frequency RF field That's why the electrical dipole radiation method is used for simulation. With the curren distribution obtained using the FDTD simulation, for various dimensional parameters th magnetic field has been calculated by electric dipole radiation method, where the curren elements are regarded as electric dipole radiation sources. The field pattern from electri dipole radiation is almost same as that from FDTD simulation. Also, it is same as that fro the result using the Viot-Savart equation, for far tone radiation term becomes zero and th Bl field amplitude of near one radiation is the same as the B field due to static current The field homogeneity is calculated in the 25 cm BSV.

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