• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.5
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• pp.217-221
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• 2005

A inductive voltage divider(IVD) is widely used as a ratio arm of precise impedance measurement bridges at low frequencies of audio frequency range and a well fabricated IVD has ratio error of $10^{-7}$ order without any calibration. Recently, the order of $10^{-8}$ of the best measurement uncertainty is needed for calibration and maintenance of impedance standards as national standards. In order to achieve that uncertainty, the IVD which is used for a ratio arm of precise impedance measurement bridge should be calibrated within the uncertain of order of $10^{-8}$ For this purpose, a ratio calibration bridge for IVDs has been developed. The measurement uncertainties of both inphase and quadrature of the bridge are analyzed less then $3{\times}10^{-8}$ respectively at 1 kHz and 25 V.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.127-132
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• 2016

This paper presents the design of a palm-sized metamaterial antenna system having reconfigurable polarization as well as dual-band characteristics. Basically, three antennas are laid by 45 degrees in order and excited by a compact metamaterial dual-band power-divider of the in-phase outputs, and the radiated fields of the antennas are mixed to turn the vector of the polarization to another. The validity of the proposed method is verified by observing the in-phase outputs from the odd-numbered power-dividing device for both 900 MHz and 2.4 GHz, and checking the changeable polarization with the antenna gain over 2 dBi for all the polarizations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.261-265
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• 1999

This paper has dealt with the design and analysis methods of the frequency characteristics for the power dividers which are extensively used in CATV and DBS systems. Therefore, the lumped-element circuits have been implemented based on the Wilkinson power divider and the characteristics of the circuits approximated to ideal transformer examined. Then the frequency characteristics are analysised by using even ㆍodd-mode method. Furthermore, in order to improve the characteristics, the optimum design method by adding compensating circuit has been proposed and it has been shown that the characteristics are improved remarkably.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.200-204
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• 2000

In this paper, we have dealt with the design and analysis methods of the frequency charateristics for the power dividers which are extensively used in CATV and DBS(Direct Broadcasting Satellite) systems. The lumped-element circuits have been implemented based on the Wilkinson power divider and the charateristics of the circuits approximated to ideal transformer examined. Then the frequency characteristics are analysised by using even - odd-mode method. Furthermore, in order to improve the charateristics, the optimum design method by adding compensating circuit has been Proposed and it has been shown that the charateristics are improved remarkably.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.233-236
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• 2005

Phase noise in a phase-locked-loop (PLL) is unwanted and unavoidable. It is a main concern in oscillation system especially PLL. The phase noise is derived in term of power spectrum density by using a reliable phase noise model. There are four noise sources being considered in this paper, which are generated by reference oscillator, voltage controlled oscillator, filter, and main divider. The major concern for this paper is the noise from the filter. Two types of second order low pass filter are used in the PLL system. Applying the mathematical phase noise model, the output noises are compared. The total noise from the passive filter is lower than the active filter at the offset frequency range between 1 Hz to 33 kHz.

• Journal of IKEEE
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• v.11 no.1 s.20
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• pp.38-45
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• 2007

A new 8-bit single-slope ADC using analog RAMP generator with digitally controllable dynamic range has been proposed and simulated for column level or per-pixel CMOS image sensor application. The conversion gain of ADC can he controlled easily by using frequency divider with digitally controllable diviber ratio, coarse/fine RAMP with class-AB op-amp, resistor strings, decoder, comparator, and etc. The chip area and power consumption can be decreased by simplified analog circuits and passive components. Proposed frequency divider has been implemented and verified with 0.65um, 2-poly, 2-metal standard CMOS process. And the functional verification has been simulated and accomplished in a 0.35$\mu$m standard CMOS process.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.543-544
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• 2008

Nowadays, the research on the system integration using various technologies, like MCM-C, MCM-L and MCM-D. Especially, MCM-D technology is suitable for mmwave application due to its high resolution of patterning and thermal property similar to that of semiconductor devices. In this work, integrated passive devices like inductor, capacitor and resistor are evaluated on the GaAs substrate and their characteristics are examined. And finally, the Wilkinson power divider using lumped IPD are evaluated on GaAs substrate and it shows low insertion loss below 0.5 dB and the isolation over 15 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.461-466
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• 2004

In this paper, the novel patch antenna for polarization diversity using switching element is presented. The proposed antenna consists of the square patch with a pair of truncated corners and a microstrip-feed line with power divider. A switching microstrip-line feed works at schottky diode ON / OFF that is placed at $\lambda$/4 point from branch-off point of power divider. Polarization diversity has two types(LHCP. RHCP) as switching the schottky diodes. The measured 3 ㏈ axial ratio bandwidth for switching operation is about 2 %.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.142-149
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• 1999

In this paper, Aperture-coupled microstrip array antenna was designed and manufactured for satellite communication at Ka-Band. We analyzed a microstrip radiation element and designed power divider using $\lambda$g/4 transformer and T-junction power divider. A manufactured Aperture-coupled $2\times2$ microstrip array antenna has a resonant frequency of 20 GHz. The experimental results are as followings : resonant frequency of 19.62 GHz, VSWR 1.0692, return loss -29.61 dB, Bandwidth 1.76 GHz and -3 dB beamwidth $42^{\circ}$.

• Journal of Families and Better Life
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• v.4 no.2
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• pp.25-34
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• 1986

This study aimed to find out the suitable design of footwear cabinet. The questionnaire data from 1969 persons of 400 families about footwear cabinet showed following results. 1) The number of shoes was related with sex, age, occupation, family income, the number of family members and educational level of housewives. 2) The size of shoes in the range of 80% of the investigated shoes was 30cm of height, 30cm of length, and 10cm of width. 3) The satisfaction with footwear cabints was mainly decided by the size and space of the cabinet. 4) Umbrella, tools and shoe polish and brush were usually kept in the footwear cabinet as well as shoes. On the basic of the results above. The size of 108cm of length (20cm for umbrella), 35cm of width and 105cm of height is sugested as the desirable footwear cabinet for the General public housing scale apartment for 5 family members and this cabinet should have 5 divider and one flexible divider by 30cm which may be adjusted by 20cm.