• Journal of electromagnetic engineering and science
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• v.16 no.3
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• pp.191-193
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• 2016

This paper proposes a voltage-controlled oscillator (VCO) that has broadband turning and low-level of phase noise characteristics. Due to the micro-strip line resonant circuit with a low Q value, which is applied to the broadband tuning range, the depreciated phase noise performance is compensated by restraining the harmonics of the oscillating frequency. The VCO was designed according to the proposed structure as well as the conventional structure, and the superiority of the proposed structure was verified through its simulation, fabrication, and measurement.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.113-118
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• 2009

This paper is about design broadband impedance matching circuit for Coupler to improve power transfer efficiency in the power line communication (PLC) system. The Tchebycheff gain function algorithm is represented to design broadband matching circuit. A practical PLC Coupler impedance matching circuit is designed, and the characteristics for S11 and S21 of PLC coupler are enhanced comparing with unmatched one. This is done by maximizing the power transfer gain from modem to the load.

• International journal of advanced smart convergence
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• v.11 no.2
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• pp.59-63
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• 2022

In this study, we study of luminescent solar concentrators comprise thick glass with broadband antireflection coating deposited on the top surfaces and inorganic phosphor layers contacted on the bottom surfaces. Solar cells are contacted to the lateral surfaces of the glass. Experimental results show the broadband antireflection coating increased the short-circuit current of the solar cell.

• Information Systems Review
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• v.6 no.2
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• pp.1-24
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• 2004

This paper develops a framework for analyzing the effectiveness of broadband network from the value chain view. The value chain of broadband network is composed of activities such as broadband network building, application/equipments development, information systems utilization. The effectiveness from the interaction between these activities are defined as the effectiveness of informatization(private and public sector) and the effectiveness of IT Industry(effects on production on inducement of broadband carriers, IT equipments and service market creation, online digital contents market creation). For testing its real-world applicability, a case study is performed on the broadband network of Korea and the effectiveness of the framework for analyzing the effectiveness of broadband network is demonstrated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.12
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• pp.1050-1057
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• 2015

This paper presents the characteristics of broadband double-cone antennas. The antenna is used to measure electromagnetic fields(2~5 GHz) radiated from a primary or a secondary electrode of a pole-transformer when partial discharge occurs inside the pole-transformer. The theoretical analysis is conducted using commercial software based on a finite difference time domain(FDTD) method. The parameters are a radius, and a height of the broadband double-cone antennas, and the number of posts on a ground plane. This paper examines influences of structural parameters of the broadband double-cone antennas on return loss. The results show that a condition for an optimum structure of broadband double-cone antennas exists. It also shows that the broadband double-cone antennas have radiation patterns similar to those of a dipole antenna. Therefore the broadband double-cone antennas are appropriate for the measurement of radiated electromagnetic fields from the pole-transformer. To verify the theoretical analysis, computed results are compared to experimental results.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.152-152
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• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.19-19
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• 2004

• ETRI Journal
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• v.27 no.3
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• pp.334-336
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• 2005

We improved the performance of the spectrum-sliced light source for wavelength-division-multiplexed passive optical networks by employing a Fabry-Perot laser diode(FP-LD). We found that the FP-LDs can suppress the intensity noise as significantly as using a gain-saturated semiconductor optical amplifier. The transmission characteristics were measured and analyzed in both conditions with and without employing an FP-LD.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.307-312
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• 2005

In this paper, the broadband FCMA(Folded Cross Monopole Antenna), which is the cross monopole antenna with the folded element, is presented. To investigate the broadband characteristics of FCMA the VSWR, the gain, and the radiation pattern are calculated in frequency between 1.75 GHz and 2.655 GHz. From the calculated result, it is shown that the presented folded cross monopole antenna has a excellent band characteristics than the existing cross monopole antenna. The presented antenna is conformed as a broadband antenna which can be used for the indoor antenna of PCS, WCDMA, Wibro, and satellite DMB band.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.483-490
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• 2011

Using a coplanar waveguide employing periodic ground structure (PGS) on silicon substrate, a highly miniaturized and broadband impedance transformer was developed for application to low impedance matching in broadband. Concretely, the multi-section transformer was designed using Chebyshev polynomials design technique for ultra broadband operation. Its size was 0.026 $m^2$ on silicon substrate, which was 8.7 % of the one fabricated by conventional coplanar waveguide on silicon substrate. The transformer showed a good RF performance over a ultra broadband from 8 - 49.5 GHz.