• Korean Journal of Optics and Photonics
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• v.13 no.1
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• pp.27-31
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• 2002

We design a 1$\times$4 optical splitter made of photonic crystal waveguides and analyze the properties of the optical splitter using the finite-difference time-domain method with perfectly-matched-layer absorbing boundaries. The photonic crystal is constructed from cylindrical rods in air on a square lattice. Our simulation results show that there are different transmission properties for four bend geometries and different incident-wave frequencies. The sum of the power transmission of the splitted light is over 93 percent at a certain geometry and frequency, and the incident power splits in the four arms with almost the same ratio.

• Journal of electromagnetic engineering and science
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• v.18 no.3
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• pp.212-214
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• 2018

The finite-difference time-domain (FDTD) model was developed to analyze electromagnetic (EM) wave propagation in an inhomogeneous ionosphere. The EM analysis of ionosphere is complicated, owing to various propagation environments that are significantly influenced by plasma frequency, cyclotron frequency, and collision frequency. Based on the simple auxiliary differential equation (ADE) technique, we present an accurate FDTD algorithm suitable for the EM analysis of complex phenomena in the ionosphere under arbitrary-direction geomagnetic field. Numerical examples are used to validate our FDTD model in terms of the reflection coefficient of a single magnetized plasma slab. Based on the FDTD formulation developed here, we investigate EM wave propagation characteristics in the ionosphere using realistic ionospheric data for South Korea.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1142-1145
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• 2006

The Finite-difference time-domain (FDTD) method is used to directly solve Maxwell's equations, and the techniques required for optical simulation of Bragg reflections of cholesteric liquid crystal (ChLC) displays are introduced in this paper. The simulated results show that the color gamut of a ChLC display can be broadened by using of a circular polarizer on top surface of the ChLC film, and are examined by experiments.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.11
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• pp.559-566
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• 2002

In this paper, we present an accurate and stable method for the solution of the transient electromagnetic response from the conducting wire structures using the time domain integral equation. By using an implicit scheme with the central finite difference approximation for the time domain electric field integral equation, we obtain the transient response from a wire scatterer illuminated by a plane wave and a conducting wire antenna with an impressed voltage source. Also, we consider a wire above a 3-dimensional conducting object. Numerical results are presented, which show the validity of the presented methodology, and compared with a conventional method using backward finite difference approximation.

• Journal of electromagnetic engineering and science
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• v.13 no.3
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• pp.158-164
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• 2013

This paper expands a previously proposed optimized higher order (2, 4) finite-difference time-domain scheme (H(2, 4) scheme) for use with lossy material. A low dispersion error is obtained by introducing a weighting factor and two scaling factors. The weighting factor creates isotropic dispersion, and the two scaling factors dramatically reduce the numerical dispersion error at an operating frequency. In addition, the results confirm that the proposed scheme performs better than the H(2, 4) scheme for wideband analysis. Lastly, the validity of the proposed scheme is verified by calculating a scattering problem of a lossy circular dielectric cylinder.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.474-483
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• 2000

In this paper, the planar LTS and Vibaldi antenna operating at 28 GHz for LMDS is optimized by finite difference time domain(FDTD) method and then fabricated and measured. We designed LTS and Vivaldi antenna with corrugation structure for reducing sidelobe, then these antenna are optimized by FDTD, and then fabricated and measured. In a results of the measured values, sidelobe level of LTS and Vivaldi antenna with corrugation structure is 4 dB lower than that of LTS and Vivaldi antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.6
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• pp.715-724
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• 1998

The FDTD(Finite-Difference Time-Domain) method is applied to analyze an unequal Wilkinson power divider. Unequal Wilkinson power divider has complex structures and the standard Yee Cell modeling method is not appropriate. In this paper, nonuniform gridding and subcell modeling are used to accurately analyze the characteristics of an unequal Wilkinson power divider. For comparison, the numerical results are presented with those from a commercial circuit simulator.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.433-436
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• 2012

We propose a novel micro surface plasmon resonance (SPR) sensor system based on polymer materials. The proposed SPR system consists of the incident medium with polymer waveguide and the gold thin film for sensing area. Using a polymer optical waveguide instead of a prism in SPR sensing system offers miniaturization, low cost, and potable sensing capability. The whole device performance was analyzed using the finite-difference time domain method. The optimum gold thickness in the attenuated total reflection mirror of polymer waveguide is around 50 nm and the resonance angle to generate surface plasmon wave is 68 degrees.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.6
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• pp.255-262
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• 2004

In this paper, a number of double-layered microwave integrated circuits (MIC) have been designed and analyzed based on a developed finite-difference time-domain (FDTD) solver. The solver was first validated through comparisons of the computed results with those previously published throughout the literature. Subsequently, various double-layered MIC printed on both isotropic and anisotropic substrates and superstrates, which are frequently encountered in printed circuit boards (PCB), have been designed and analyzed. It was found that in addition to protecting circuits, the added superstrate layer can increase freedoms of design and improve circuit performance, and that the FDTD is indeed a robust and versatile tool for multilayer circuit design.