• 한국전자파학회논문지
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• 제8권2호
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• pp.107-115
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• 1997

본 논문에서는 23 GHz 국간(Point-to-point) 통신용 Push-Push발진기를 Split Ring 공진기(Split Ring Resonator)를 사용하여 설계, 제작하였다. Split Ring 공진기(SRR)는 둥가회로를 이용한 이론적인 해석 및 MPIE(Mixed Potential Integral Equation)수칙해석 툴을 이용 해석하였다. 이 해석된 결과를 사용하여 전송 모드로 마이크로 스트립 라인과 결합된 SRR를 분석하였다. 제작된 발진기은 23 GHz에서 출력 전력은 4dBm, 기본 주파수 및 3차 고조파 억제는 - 20 dBc, - 34 dBc의 특성과 발진주파수에서 1 MHz offset에서 -109 d dEc/Hz의 SSB위상잡음 및 1.4%의 변환 효율을 나타내었다. 이 실험결과는 이론 및 시뮬레이션 결과와 일치함을 알 수 있다.

• 한국정밀공학회지
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• 제21권4호
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• pp.170-178
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• 2004

Continuously variable transmission (CVT) mechanisms considered here are input coupled types that combine the functions of a 2K-H II type differential gear and a V-belt type continuously variable unit (CVU). For the 8 different mechanisms, 4 of them are power-circulation modes while the other 4 are power-split modes, various performance analysis (speed ratios, power flows, divisions of power transmission in a differential gear and a CVU, and theoretical efficiencies) are performed to vary design parameters. Experimental studies are executed to validate fundamental relations (speed ratios, power flows, efficiencies, occurrence of geared neutral). Some useful characteristics associated with performance also are discussed in the mechanisms.

• International Journal of Precision Engineering and Manufacturing
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• 제3권3호
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• pp.28-36
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• 2002

The continuously variable transmission (CVT) mechanism considered here is the output coupled type which combines the functions of a 2K-H I type differential gear unit and a V-belt type continuously variable unit (CVU). One shaft of the CVU is connected directly to the output shaft and another shaft of it is linked to the differential gear unit. It is shown that some fundamental relations (speed ratios, power flows and efficiencies) for twelve mechanisms previously described are valid by various experimental studies, six of them produce a power circulation and the others produce a power split. Parametric analysis is carried out in relation to the efficiency, speed ratio and power ratios in order to assist in the design of an optimum configuration. Some useful properties associated with power flow modes also are discussed in the output coupled type continuously variable transmission.

• 한국기계가공학회지
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• 제15권5호
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• pp.57-65
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• 2016

The power flow of an 8-speed automatic transmission was analyzed using a lever analogy for the manufacturing of planetary gears. From the analysis, we found that the engine power was split between the first and second double-pinion planetary gears (DPPG1 and DPPG2), and was then passed to the DPPG3 for the fourth speed. For the fifth speed, the engine power was split between the DPPG1 and DPPG3. For the speeds 6-8, the engine power was passed only to SPPG2, while the seventh speed contained the power circulation.

• 대한전자공학회논문지TC
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• 제44권11호
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• pp.54-59
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• 2007

본 논문에서는 varactor-loaded split-ring resonator (VLSRR)를 기반으로 한 가변 metamaterial 전송 선로를 이용한 광대역 전압 제어 발진기를 제안하였다. 우선, 마이크로스트립 라인에 결합된 VLSRR이 주파수 조절 특성을 갖는 metamaterial 전송선로를 만들 수 있음을 증명하였다. 음의 유효 투자율은 VLSRR에 의해 공진 주파수 상에서 협대역으로 얻어지는데, 버랙터 다이오드들의 연결을 통해 주파수가 조절될 수 있다. 1.8 V의 공급 전압을 갖는 전압 제어 발진기는 주파수 조절 범위 $5.407\;{\sim}\;5.84\;GHz$에서 $-108.84\;{\sim}\;-105.5\;dBc/Hz$ @ 100 kHz의 위상 잡음 특성을 얻는다. Power-frequency-tuning-normalized (PFTN)이라고 불리우는 figure of merit (FOM)은 20.144 dB이다.

• 전력전자학회논문지
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• 제17권4호
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• pp.359-367
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• 2012

In this paper, the input split type series-parallel hybrid electric vehicle (SPHEV) is established and the interpretation of the dynamic characteristics in four kinds of HEV modes, such as electric vehicle mode, engine mode, hybrid mode, and regeneration mode, is described. For this research, the forward-facing approach simulation method is chosen, which is useful for vehicle dynamic analysis. The rating of each powertrain component is designed based on energy-based concept and electrical peaking hybrid (ELPH) method. Finally, the designed powertrain is evaluated with the developed PSiM simulator and simulation results are shown.

• Journal of electromagnetic engineering and science
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• 제4권4호
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• pp.150-155
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• 2004

Universal design equations are presented for the H-plane T-junction power divider with a circular conducting post in a rectangular waveguide. For a given operating frequency and power split ratio, the post offset from the T-junction center line, the distance between the post and the waveguide wall, and the post diameter can be adjusted to obtain a minimum reflection at the input waveguide. Optimum values of the post offset are given in terms of the normalized frequency and the power split ratio. Corresponding values of the post diameter and the distance of the post from the waveguide wall are given in terms of the normalized frequency and the post offset.

• 대한기계학회논문집A
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• 제26권6호
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• pp.1060-1068
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• 2002

Compound continuously variable transmission(CVT) mechanisms are proposed, which can offer a backward mode, a geared neutral, an underdrive mode and an overdrive mode. They are composed of a 2K-H I type differential gear unit, a V-belt type continuously variable unit(CVU), a few friction clutches and gears, and not required of a starting device as a torque converter. Compound CVT mechanisms developed here present two distinct operating modes which are a power circulation mode and a power split mode. The transition of two modes takes place at the particular CVU speed ratio. For these CVT mechanisms, performance analysis related to speed ratio, power ratio and efficiency are executed and proven by experimental studies.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.739-742
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• 1997

Continuously variable transmission(CVT) mechanisms are proposed, which can offer a backward mode, a geared neutral, an underdrive mode and an overdriver mode. They are not required of a starting device as a torque converter. CVT mechanisms developed here present two distinct operating modes which are a power circulation mode and a power split mode. The transition of two modes takes place at the particular CVU speed ratio. For these CVT mechanisms, performance analysis related to speed ratio, power ratio and theoretical efficiency are executed.

• Journal of electromagnetic engineering and science
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• 제16권1호
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• pp.52-56
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• 2016

This paper suggests a class-F power amplifier with split open-end stubs to provide a broadband high-efficiency operation. These stubs are designed to have wide bandwidth by splitting wide open-end stubs into narrower stubs connected in shunt in an output matching network for class-F operation. In contrast to conventional wideband class-F designs, which theoretically need a large number of matching lines, this method requires fewer transmission lines, resulting in a compact circuit implementation. In addition, the open-end stubs are designed with slant ends to achieve additional wide bandwidth. To verify the suggested design, a 10-W class-F power amplifier operating at 1.7 GHz was implemented using a commercial GaN transistor. The measurement results showed a peak drain efficiency of 82.1% and 750 MHz of bandwidth for an efficiency higher than 63%. Additionally, the maximum output power was 14.45 W at 1.7 GHz.