• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 C
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• pp.597-599
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• 2000

In this paper, Dielectirc waveguides have been calculated using the vector finite element method. This method is introduced that allows propagation constants and electric field distribution to be computed directly. In order to obtain more accurate solutions, Second order vector elements are proposed.

• 한국군사과학기술학회지
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• 제11권6호
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• pp.148-155
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• 2008

We investigated the damage effects of microcontroller devices under high power electromagnetic(HPEM) wave. HPEM wave was radiated from the open-ended standard rectangular waveguide(WR-340) to free space. The influence of different reset-, clock-, data-, and power supply-line lengths has been tested. The susceptibility of the tested microcontroller devices was in general much influenced by clock-, reset-, and power supply-line length, little influenced by data-line length. Further the line length was increased, the malfunction threshold was decreased as expected, because more energy couples to the devices. The surfaces of the destroyed microcontroller devices were removed and the chip conditions were investigated with microscope. The microscopic analysis of the damaged devices showed component and bondwire destructions such as breakthroughs and melting due to thermal effects.

• Journal of the Optical Society of Korea
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• 제12권1호
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• pp.13-18
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• 2008

We numerically investigate by the finite-difference time-domain method the effects of surface termination on directional emission exiting a photonic crystal waveguide. The directed power and far-field beam profile for the original proposal [E. Moreno et al., Phys. Rev. B 69, 121402 (2004)] and its enhancement [S. K. Morrison et al., Appl. Phys. Lett. 86, 081110 (2005)] are computed for different values of some important parameters. We find another surface termination condition with a positive surface displacement in the structure of the original proposal which has a negative surface displacement. Our surface termination is more effective than the original structure, and nearly as effective as the termination for the enhancement, for directional emission. Besides, our termination is simpler than that for the enhancement. We confirm the effectiveness of directional emission from our termination in its far-field beam profile, radiation intensity distribution, and additionally the wave-vector space representation by the Fourier analysis.

• Journal of the Optical Society of Korea
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• 제18권6호
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• pp.679-684
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• 2014

Enhanced analysis is performed to design a wedge projection system with a slab structure that increases the projected image size. The specification values of the system such as the length of the slab structure and the imaging region are calculated and investigated using an optical simulation tool. We also propose a split imaging region method to represent a large tiled scene using the thin wedge waveguide structure. Experiments are performed to verify the feasibility of the proposed method.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.157-160
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• 1998

The analysis of a coaxial cable with periodic slots as a leaky-wave antenna is considered. The mode matching method and method of moments with Galerkin testing procedure is then used to obtain the determinantal equation for the unknown leaky-wave propagating constant. Both technigues allow the fields to be obtained in any region, and the radiation characteristics of the structure. By resorting to a suitable numerical techniques, it is possible to calculate the leaky-wave propagating constants and the radiation patterns. Numerical results demonstrate the validity of the technique.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.52-54
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• 2011

본 논문에서는 효율적인 전자계 시뮬레이터를 구축하기 위하여 프레임워크를 설계하고 그 효용성을 검토하였다. 특히 여러 대의 네트워크 PC를 이용한 병렬화를 통하여 계산에 이용되는 PC의 수에 비례하여 계산시간이 단축되는 것을 확인하였다. 본 연구를 통하여 복잡한 구조를 가진 안테나, 공진기, 도파기 등의 설계 및 해석에 적용 가능할 것으로 기대된다.

• 전자공학회논문지A
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• 제32A권6호
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• pp.19-28
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• 1995

In this paper, measured iris transmission loss data and simulated data by using 3-dimension full-wave analysis S/W are presented and compared with Marcuvitz's theory. And by using measured iris data, dual-mode narrow-band channel filters can be successfully implemented. This paper shows that there is severe difference between the transmission loss of iris calculated by using Marcuvitz's equation to calculate iris dimension, if the length of slot iris is longer than .lambda./.pi., and in the long urn the response of channel filter is distorted. Experimental result shows that the characteristic response of implemented channel filter by using the iris transmission loss graph presented here matches well the design specfications. In conclusion, iris transmission loss measurement method will be very useful to design channel filter.

• 한국음향학회지
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• 제16권6호
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• pp.19-24
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• 1997

성덕 대왕 신종 상단부에 위치한 음통의 음향학적 역할을 규명하기 위하여 현장 실험을 수행하고 관찰된 현상을 설명하기 위한 모델을 제안하였다. 실험을 통하여 음통의 음향학적 특성을 대표하는 음통 출구단의 반사 계수, 방사 임피던스를 측정한 결과, 음통이 저주파(이경우 300Hz 이하)에서는 거의 모든 소리를 종 내부로 되돌리는 특성을 보이며, 그 이상의 고주파 성분은 효과적으로 종 밖으로 방사하는 특성을 갖고 있음을 확인하였다. 또한 음통에 대한 음향학적 모델링 및 이를 바탕으로 한 수치적 분석을 수행하였으며 실험결과와 대체적으로 경향이 일치하는 결과를 보여주고 있다.

• International journal of advanced smart convergence
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• 제1권2호
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• pp.43-46
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• 2012

We analyzed a periodic thick mushroom structure for use as an artificial magnetic conductor using mode-matching method. The fields in each region were represented by either Floquet modes or waveguide modes. By applying tangential electric and magnetic field continuity conditions and using matrix equations, unknown coefficients and dispersion diagram were calculated. The proposed model can account for the effects of oblique incidence. Simulation time using the method was much faster than the commercial tools. We found that the current method produces accurate results of reflection phase and dispersion diagram.

• 전자공학회논문지A
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• 제32A권9호
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• pp.1244-1249
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• 1995

Wavelet transform technique is applied to two important electromagnetic problems:1) to analyze the frequency-domain radar echo from finite-size targets and 2) to the integral solution of two- dimensional electromagnetic scattering problems. Since the frequency- domain radar echo consists of both small-scale natural resonances and large-scale scattering center information, the multiresolution property of the wavelet transform is well suited for analyzing such ulti-scale signals. Wavelet analysis examples of backscattered data from an open- ended waveguide cavity are presented. The different scattering mechanisms are clearly resolved in the wavelet-domain representation. In the wavelet transform domain, the moment method impedance matrix becomes sparse and sparse matrix algorithms can be utilized to solve the resulting matrix equationl. Using the fast wavelet transform in conjunction with the conjugate gradient method, we present the time performance for the solution of a dihedral corner reflector. The total computational time is found to be reduced.