• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.46-48
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• 1995

An efficient technique for the analysis of a general class of microstrip structures with a substrate is applied in this paper using newly-derived closed-form spatial domain Green's functions employed in conjunction with the Method of Moments(MoM). The computed current distributions on the microstrip structures are used to determine the scattering parameters of microstrip discontinuties and the input impedances of microstrip patch antennas. It is shown that the use of the closed-form Green's functions in the context of the MoM provides a computational advantage in terms of the CPU time by almost two orders of magnitude over the conventional spectral domain approach employing the transformed version of the Green's functions.

• 전자공학회논문지D
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• 제34D권9호
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• pp.28-35
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• 1997

A novel high-Q vertical jinductor for MMICs is proposed and characterized in a wide range of frequencies (DC~10 GHz) using the numerical methods such as the PeEC(partial equivalent element circuit), the FDM (finite difference method) and the MoM (method of moments). Electrical superiority of the vertical inductor to the horizontal is observed in terms of the magnetic flux linkage and the ground screening effect. The veritcal bondwire inductor is designed in consideration of the wire bonding feasibility and the optimum electrical peformance. This structure is also analyzed using the equivalent circuit and compared with the conventional spiral inductors From the calculated results, high Q-factor, inductance, and cut-off frequency are observed to be inherent characteristics of the veritcal bondwire inductor.

• 한국산학기술학회논문지
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• 제16권10호
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• pp.7189-7195
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• 2015

모멘트법(MoM)인 TE(transversw electric) 전장 적분 방정식(EFIE)으로 완전 전기도체(PEC) 원통을 산란 해석하였다. 이 과정에서 나타나는 특이점(singlarity)과 과대 특이점(hypersingularity)을 포함한 적분 계산은 어렵기 때문에 수치해석 방법으로 특이점을 고립시켜 자체항(self-term)을 얻었다. 모멘트법에서 base 함수와 test 함수의 선택은 수치해석 결과의 정확도와 수렴에 있어 매우 중요한 요인이됨은 알려져 있는 사실이다. basis 함수와 test함수를 달리하여 세 가지 방법으로 PEC 원통에 유도된 전류를 구하였다. 이렇게 구한 결과를 해석학적 방법과 모멘트법에서 얻은 전류와 비교하여 상대 효율 전류 오차를 구하였으며 어떤 결합 방법이 효율적인지 확인하였다. 또한 각 결합방법에 따른 상대 효율 전류 오차의 수렴율을 구하여 가장 정확한 결과를 얻을 조건을 찾았다. 전류 오차의 가장 빠른 수렴오더(order of convergence) 2.528은 펄스 base 함수/델타 test 함수 결함 조건에서 얻었다.

• 전자공학회논문지D
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• 제34D권2호
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• pp.1-9
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• 1997

For the reduction of parasitic inductance and matching of bonding wire in the package of microwave devices, we propose multiple bonding wires buried in a dielectric material of FR-4 composite. This structure is analyzed using the method of moments (MoM) and compared with the common bondwires and ribbon interconnections. The FR-4 composite is modelled by the cole-cole model which can consider the loss and the variation of the permittivity in a frequency. At 20 GHz, the parasitic reactance is reduced by 90%, 80%, 60% compared to those of a single bonding wire in air, double bonding wires in air and ribbon interconnection in air, respectively. Also, the new bondwire shows very good matching of 60.ohm characteristic impedance and has 15dB, 10dB, 5dB improvement of the return loss and 2.5dB, 0.7dB, 0.2dB improvement of the insertion loss compared to the common interconnections. This technique can minimize the parasitic effect of bondwires in microwave device packaging.

• 전자공학회논문지D
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• 제34D권2호
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• pp.21-26
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• 1997

The dielectric effects on the parasitics of bondwires buried in slightly-lossy dielectric materials hav been investigated over a wide frequency range using the method of moments with incorporation of ohmic and dielectric losses. The FR-4 composite is widely used as a basis material for PCB and plastic packages, because of it sinherent electricl and chemical stbility and low cost. The cole-cole model, which is representative complex permittivity model of epoxy polymers, has been applied to consider the dielectric effects in the MoM calculation. The prasitic impedance of a grounded bondwire in FR-4 composite is greatly increased due to the dielectric loading effect enhanced by the radiation at high frequencies. These calculation results will be helpful for designing and packaging of high-frequency low-cost IC's.

• 전자공학회논문지D
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• 제34D권6호
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• pp.20-32
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• 1997

An optimum parasitic inductance is observed for maximizing the modulation bandwidth of the multiple quantum well (MQW) electro-absorption optical modulator. For 1.1 pF device cpaacitance of the current MQW optical modulator, the optimum parasitic inductances for maximum bandwidth are calculated for different terminating resistors. In ase of 50.ohm. terminating resistor, the 3-dB modulation bandwidth can be increased 45% wider by using the optimum parasitic inductance than nothing parasitic inductance. This calculated optimum inductance can be practically implemented, since the parasitic inductance of bondwires can be accurately analyzed using the method of moments (MoM) and controlled by changing the length and shpae of bondwires.

• 한국전자파학회논문지
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• 제11권7호
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• pp.1204-1210
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• 2000

슬롯 개구를 통해 평향평판 도파관 내부를 결합되어지는 전자파 펄스(EMP)의 과도 응답을 해석하기 위한 방법을 제안하였다. 개구의 미지 등가 면 자기전류밀도에 대한 혼합 포텐셜 적분 방정식(MPIE)을 세웠고 평행평판 도파관 영역에서의 백터 및 스칼라 포텐셜 그린함수를 개선된 북소영상법을 사용하였을 때 closed form 그림함수를 사용한 결과를 계산시간을 현저히 줄일 수 있었고 본 논문이 제안한 방법의 타당성을 확인하기 위해 기존 방법의 해석결과와 비교해 보았을때 본 논문의 해석결과와 비교적 잘 일치함을 알 수 있었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권12호
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• pp.626-633
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• 2004

In this paper, we present a time domain combined field integral equation (TD-CFIE) formulation to analyze the transient electromagnetic response from three-dimensional dielectric objects. The solution method in this paper is based on the method of moments (MoM) that involves separate spatial and temporal testing procedures. A set of the RWG (Rao, Wilton, Glisson) functions Is used for spatial expansion of the equivalent electric and magnetic current densities and a combination of RWG and its orthogonal component is used as spatial testing. We also investigate spatial testing procedures for the TD-CFIE to select the proper testing functions that are derived from the Laguerre polynomials. These basis functions are also used for temporal testing. Use of this temporal expansion function characterizing the time variable enables one to handle the time derivative terms in the integral equation and decouples the space-time continuum in an analytic fashion. Numerical results computed by the proposed formulation are presented and compared with the solutions of the frequency domain combined field integral equation (FD-CFIE).

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.329-334
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• 2017

This paper discusses the near field characteristics of a dipole source located near conducting metallic walls from an electromagnetic compatibility (EMC) point of view. An integral equation for a dipole source near a metallic wall is derived and solved by applying Galerkin's method of moments (MoM). The results show that in the regions outside the dipole source, total electric near fields decrease gradually in magnitude with an increasing field point from the dipole source. But in the regions inside the dipole source, total electric near fields decrease rapidly with a dipole position of $h{\leq}0.3{\lambda}$. For a dipole position of $h{\geq}0.7{\lambda}$, the peaks and nulls of the total near electric field occur periodically in the regions inside the dipole source, and the fluctuation period is almost $0.5{\lambda}$. The worst position for a receptor location is along the z-axis, and a range of a half-magnitude of the maximum near electric field in the principal H-plane is about two times broader than that of the principal E-plane. Experimental measurements are also presented to validate the theory.

• 한국전자파학회논문지
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• 제15권4호
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• pp.368-378
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• 2004

본 논문에서는 finite-extent backed conductor를 가지는 CPW(Coplanar waveguide) 방향성 결합기에서, 방향성의 향상을 위해 접지면과 전송선 사이의 slot 폭을 확장하는 보상구조를 제안하였다. 제안된 구조는 적절한 slot의 길이와 폭을 가질 경우, 결합기에서의 변화되는 정전용량과 추가된 인덕턴스로 인해 각모드의 위상속도 차이가 없어지므로 우수한 방향성 특성을 갖게 한다. 제안된 보상구조를 이용하여 1 ㎓를 중심주파수로 하는 finite-extent backed conductor를 가지는 CPW 방향성 결합기를 보통의 결합도를 갖는 6 ㏈ 결합기와 높은 결합도를 갖는 3 ㏈ 결합기 형태로 구현하였다 설계된 CPW 방향성 결합기는 MoM(Method of Moments) 방식의 EM solver 계산 결과, 중심주파수에서 목적하는 결합도를 가지면서 각각 55 ㏈와 58 ㏈의 우수한 방향성을 가지며, 정합특성 역시 우수하다. 측정결과는 계산결과와 매우 유사하며, 이를 통하여 제안된 보상구조의 유용성을 확인하였다.