• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.712-712
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• 2006

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.261-261
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• 2006

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.443-444
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• 2008

A double-balanced frequency up-converter using the Gilbert cell structure has been designed with the TSMC $0.18\;{\mu}m$ CMOS library. The frequency up-converter consists of a Mixer core and IF / LO balun. Frequency Up-converter exhibits a 3.4 dB conversion gain with a - 7.6 dBm $P_{1dB}$ for IF power of -10 dBm and LO power of 0 dBm inputs. It also exhibits 92.2 % modulation depth as a ASK modulator.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.346-349
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• 2003

A SiGe HBT MMIC double balaced up-converter has been designed and fabricated for C-band WLAN applications. The up-converter is based on the Gilbert cell mixer with an active baluns for differential inputs of LO and IF signals. The designed up-converter exhibits a conversion gain 12.5dB for a -10 dBm LO power. It also exhibits LO-RF isolation of 19.3dBc, and IF-RF isolation of 23.3 dBc at a 1-dB compression point of -14.2dBm

• Journal of Sensor Science and Technology
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• v.13 no.2
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• pp.133-138
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• 2004

Today, the obstacle detection system has massive size and restrictive detection range. To solve these problems, this paper proposes the capacitance variation detector using the variated capacitance value as a result of the obstacle approaching. If obstacle approaches, the capacitance value of capacitance sensor is increased and the operating frequency of oscillator is decreased. Then this changed frequency appears to the output of the mixer that operate down conversion. The capacitance variation detector is produced by Hynix$0.35{\mu}$ CMOS process. In experiment result, the frequency of final output is 6.81 MHz at no obstacle and 31.45 MHz at approaching obstacle. In conclusion, proposed capacitance variation detector has small size, low power consumption and easiness to set up anywhere. So it is expected to substitute the obstacle detector.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.227-230
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• 2001

본 논문은 마이크로파 슈퍼헤테로다인 수신기에서 발생되는 이미지성분을 효과적으로 제거하기위한 Cascode형 FETs구조를 이용한 Ku-Band 이미지 제거용 자기발진믹서을 분석하였다. 자기발진믹서는 두개의 FET에 의해서 동작되며 상위 FET는 유전체공진기에 의해서 발진기로 동작하며, 아래쪽 FET는 믹서로 동작시켰다. 모의실험 결과 초기 게이트바이어스 전압은 $V_{ gsl}$=-0.4V와 $V_{g2}$=-0.4V와 $V_{g2}$V선정 하였으며, 10.75GHz의 발진기 출력은 2.249dBm, 위상잡음은 -137.9dBc/1000KHz, 이미지 제거특성은 약 -26dBc 값을 얻었다.얻었다.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.406-411
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• 2005

In this paper, we propose an active 90$^{\circ}$ phase divider for application to MMIC. Because of their very large size, conventional passive 90$^{\circ}$ dividers can't be integrated on MMIC. Therefore, highly miniaturized 90$^{\circ}$ dividers are required for a development of highly integrated MMIC. For this reason, active 90$^{\circ}$ divider is indispensable because active phase divider is much smaller than conventional passive dividers, and it can be integrated on MMIC. In this work, we developed active 90$^{\circ}$ divider with emitter inductor, and it was employed for the operation of the balanced mixer in order to verify the performance of the active 90$^{\circ}$ divider. According to the results, it was found that the active 90$^{\circ}$ divider exhibited good RF performances comparable to conventional passive power dividers.

• Journal of computational fluids engineering
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• v.14 no.4
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• pp.1-6
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• 2009

In the present study, numerical simulations were performed in a stirred solid/liquid system by using Eulerian multi-phase model. The transient flow field of liquid and distribution of solid particles were predicted in the stirred tank with pitched paddle impeller and baffles. The Frozen rotor method is adopted to consider the rotating motion of the impeller. The effects of number and width of baffles on the mixing time and the quality of solid suspension in the stirred tank are presented numerically. The result shows that the mixing time decreases as the width and number of baffles increase. The present numerical methodology can be applied to optimizing mixing condition of industrial mixer.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.2 s.25
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• pp.103-110
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• 2006

We present a W-band radiometer to detect the metal targets on the ground environment. The type of the designed radiometer is the total power radiometer(TPR) for the simple configuration. The front end of the TPR consists of only the Mixer and LO for miniaturizing the system. Because the radiometer system does not use the low noise amplifier, we use matching circuits and a diode detector configured as a voltage doubler to compensate the degradation of sensitivity. We solve the temperature variation problems by filtering the reference voltages of the radiometer output signals. Through some experiments, we have verified that the designed radiometer system has good performances in detecting metal targets lying at several hundred meters.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.131-135
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• 2002

The reclamation of food waste is brought by law in order to clean the underground water. Thus the food waste feed back system should be prepared. The electric heater and mixing tool for FIR radiation were developed in order to control the food waste fermentation. Also we suggest the optimum temperature 19$0^{\circ}C$, black enamel ware for food waste control.