• 한국군사과학기술학회지
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• 제3권1호
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• pp.155-163
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• 2000

A general characterization procedure based on the extraction of a 2n-port admittance matrix corresponding to n uniform coupled lines on the multi-layered substrate using the Finite-Difference Time-Domain (FDTD) technique is presented. The frequency-dependent normal mode parameters are obtained from the 2n-port admittance matrix, which in turn provides the frequency-dependent distributed inductance and capacitance matrices. To illustrate the technique, several practical coupled line structures on multi-layered substrate, including a three-line structure, have been simulated. It is shown that the FDTD based time domain characterization procedure is an excellent broadband simulation tool for the design of multiconductor coupled lines on multilayered PCBs as well as thick or thin hybrid structures.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권4호
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• pp.260-266
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• 2007

Analytical compact form models for the signal transients and crosstalk noise of inductive-effect-prominent multi-coupled RLC lines are developed. Capacitive and inductive coupling effects are investigated and formulated in terms of the equivalent transmission line model and transmission line parameters for fundamental modes. The signal transients and crosstalk noise expressions of two coupled lines are derived by using a waveform approximation technique. It is shown that the models have excellent agreement with SPICE simulation.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.611-621
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• 2003

A spurious-suppressed transversal filter using the multiple-coupled line is proposed. The frequency characteristics of the multiple-coupled line are analyzed in detail. In order to compare the performances, the novel spurious-suppressed transversal filter using triple-coupled half-wavelength directional couplers is designed at 5 GHz. The spurious-suppression characteristics of the proposed transversal filter are verified by the full wave analysis and the measurement. The spurious response of the fabricated filter is effectively suppressed up to 13 GHz and the large attenuation is attained in the stopband.

• Journal of Electrical Engineering and information Science
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• 제1권2호
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• pp.96-100
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• 1996

This paper describes a concrete method for computing characteristic impedances and effective dielectric constants of the microstrip coupled lines without and with a dielectric overlay. The frequency-independent spectral domain method is used for the analysis of these lines. This method is a powerful, accurate, and numerically efficient approach for planar transmission line structure. For designing the optimal directional coupler, the velocities of even and odd mode must be equal but velocities of these two modes are different in the conventional coupled line which is inhomogeneous. The results show that these two velocities can be almost same according to variations of structural and material parameters in terms of the overlay(superstrate).

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.350-353
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• 2003

In this paper, we designed and implemented a 10dB directional coupler with high directivity using branch line structure. The characteristic impedance of parallel branch line for 10 dB directional coupler is about 150 $\Omega$. To realize high characteristic impedance in microstrip line, we used the coupled line structure. The directional coupler were implemental and measured. The measured results show that the directivity is high than 24 dB.

• KSBB Journal
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• 제4권2호
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• pp.118-122
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• 1989

Candida utilis를 model균주로 하여 세포증식과 기질소모를 on-line 간접측정하고자 개인용 컴퓨터(IBM PC-AT)와 interface된 quadrupole mass spectrometer로 발효 배기가스를 분석하였다. 5분마다 연속적으로 분석되는 질소, 산소, 이산화 탄소 및 수증기의 mole백분율(%)로부터 산소 소비속도(OUR)와 이산화 탄소 발생속도(CER)를 on-line으로 계산하였다. 미리 실험 결과치로부터 결정한 maintenance와 수율 상수들($k_1k_2 $ 값을 이용하여 세포농도와 기질인 포도당의 농도를 on-line으로 간접추정하였다. 간접추정된 값들은 실험적으로 측정한 세포농도 및 기질농도와 잘 일치함을 알 수 있었다.

• 한국미생물·생명공학회지
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• 제17권3호
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• pp.241-246
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• 1989

Quadrupole mass spectrometer를 이용한 발효 배기가스의 분석을 통해 세포의 증식을 on-line monitoring하고자 model 균주로 Candida utilis에 대해 연구하였다. Quadrupole mass spectrometer와 interface된 16-bit 개인용 컴퓨터 (IBM PC-AT)에서 산소 소비속도(OUR)와 이산화탄소 발생속도(CER)를 on-line 계산할 수 있었고 계속해서 이들 계산치로부터 세포농도와 증식속도 및 비증식속도를 계산하였다. 계산된 값들은 실험적으로 측정한 세포농도 및 비증식속도와 잘 일치함을 알 수 있었다.

• 한국정보통신학회논문지
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• 제15권10호
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• pp.2065-2071
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• 2011

본 논문에서는 마이크로스트립 선로 공진기와 입출력 단자의 결합 위치에 따른 공진기의 외적 양호도를 위상 특성을 이용하여 구하는 방법을 제시한다. 마이크로파 필터 설계에서 단자 접속 구조로 많이 이용되는 접합 선로 구조와 결합 선로 구조에 대해 단자의 위치와 선로의 폭과 간격에 따른 결과를 제시한다. 이 방법으로 정확한 $Q_e$ 값을 얻을 수 있었고, 이 결과는 결합공진기 필터 설계에 응용될 수 있다.

• 한국전자파학회논문지
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• 제14권6호
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• pp.591-598
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• 2003

3중 결합 구조의 방향성결합기로 구성된 새로운 구조의 트랜스버살 필터를 제안하였으며 sinc 함수를 이용하여 제안된 필터의 결합계수를 간단하게 구하는 방법도 소개하였다. 최고 -3 dB의 결합도를 갖는 일반적인 방향성결합기를 이용한 기존의 트랜스버살 필터는 방향성결합기 사이를 연결해 주는 연결선로의 영향에 의해 주파수 특성이 저하되는데 제안된 구조의 필터는 특성 저하 현상이 현저히 개선되며 또한 높은 결합도가 요구되는 광대역 필터의 경우 삽입손실 특성이 우수하다. 그리고 같은 통과대역폭의 경우 방향성결합기와 연결선로의 수가 기존 필터보다 적으며 집적도에 더 유리한 구조를 가지고 있다. 제안된 구조의 필터 특성을 제작을 통해 고찰하였으며 계산치와 비교하였다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.41-45
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• 2006

The fabrication process of fiber placement system of carbon fiber reinforced plastic (CFRP) requires real time process control and reliable inspection to ensure quality by preventing defects such as delamination and void. Therefore, novel non-contact inspection technique is required during the non-destructive evaluation in a fiber placement system. For the inspection of delamination in CFRP, various methods to receive laser-generated ultrasound were applied by using piezoelectric transducer, air-coupled transducer, wavelet transform and scanning laser ultrasonic technique. Laser-generated ultrasound was received with a conventional piezoelectric sensor in contacting manner. Then signal characteristics due to defects were analyzed to find a factor for detecting defects. Air-coupled transducer was used for reception of laser-generated guided wave using linear slit array in order to generate high frequency guided wave. And line scan technique was used to confirm the capability of on-line application. The high frequency component of laser-generated guided wave received with piezoelectric sensor disappeared after propagating through delamination region. Nevertheless, it was failed to receive high frequency guided wave in using air-coupled transducer. The first peak of the frequency spectrum under 100kHz in the delamination region is higher than in the sound region. By using this feature, the line scanned frequency data were acquired in fully non-contact generation and reception of ultrasound. This method was proved as useful technique for detecting delamination in CFRP.