• Journal of electromagnetic engineering and science
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• v.17 no.1
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• pp.9-13
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• 2017

In this work, a broadband composite right/left-handed (CRLH) half-mode substrate integrated waveguide (HMSIW) quadrature Wilkinson power divider is proposed. The proposed CRLH-HMSIW quadrature power divider includes a microstrip Wilkinson power divider on the transition structure between the microstrip and HMSIW, and two thru transmission lines for the HMSIW and the CRLH-HMSIW. The measured amplitude, phase difference and isolation between the two output ports of the proposed structure have 1 dB, ${\pm}5^{\circ}$ and less than -15 dB in a wide frequency range of 4.1-6.68 GHz with 47.9% bandwidth, respectively.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1777-1782
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• 2016

A compact and broadband balun is designed using a conventional right-handed transmission line (RHTL) and a left-handed transmission line (LHTL) with lumped elements only. The proposed balun maintains a phase difference of $180^{\circ}{\pm}12^{\circ}$ at the output ports for the frequency range of 1.27 GHz-2.69 GHz. Nevertheless, the circuit size is merely $9.5mm{\times}12.7mm$. To verify the performance of the proposed balun, we attached it to a dipole-type antenna and observed that the return loss is greater than 10 dB for the frequency range between 1.86 GHz and GHz. The radiation pattern and peak gain are similar to those of the dipole antenna with a conventional balun.

• Journal of Korean Library and Information Science Society
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• v.33 no.3
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• pp.327-358
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• 2002

The study has Proceeded through examining and analyzing related laws and articles on library exemption relating to reproduction and transmission in digital environment. First of all, the study investigates and analyzes in detail the changes and characteristics of the regulation of library exemption in WCT, EU, U.S., Japan, and Australia. After analyzing of the article 28 in current Copyright Act and amended proposal for Copyright Act in Korea, it found the regulation to be inadequate. As a result of the legal analysis, this paper is proposing a revised plan of the article 28 in the Copyright Act of Korea.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.68
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• pp.1-21
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• 2015

The purpose of this study is to propose a new mechanism for the global transmission of electronic trade documents and to promote them using it. Trade settlement methods are changed from L/C bases to non-L/C bases and in particular, the telegraphic transfer is dramatically increased since mid 1990. But the status of transmission of electronic trade documents still rely on the letter of credit and bill of lading. So it need to change the process of transmission of electronic trade documents utilizing non-negotiable sea waybill instead of bill of lading. In this study, I pointed out two problems as obstacle factors in global transmission of electronic trade documents. First is the system connection problem between domestic and foreign banks and second is the electronic right transfer problem in the bill of lading. Electronic bill of lading has already been made, but are not used and e-Nego has also not been activated under the above issues. Therefore, it should be solved previously the above problems for the global transmission of electronic trade documents under the letters of credit. However, in transactions of transfer, it does not need the inter-bank connection and also does not occur the electronic right transfer problem of bill of lading if using the non-negotiable seaway bill instead of bill of lading. In this paper, I recommend the global transmission strategies of e-trade documents using the non-negotiable sea waybill in transactions of transfer. Hopefully, I expect the activation of global transmission of e-trade documents through the utilization of electronic non-negotiable sea waybill as suggested by this study.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.571-577
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• 2011

This paper presents a novel balanced filter design based on a metamaterial structure applicable to differential-mode excitation. The metamaterial structure is based on a unit-cell which under a differential-mode excitation behaves like composite right/left-handed(CRLH) metamaterial with filter characteristics. In contrast, the metamaterial unit-cell is below cut-off under a common-mode excitation. Experimental results are used to verify the proposed metamaterial's differential-mode characteristics. The metamaterial is fabricated with a balanced filter design resulting in an operating frequency range of 960~1000 MHz with a insertion loss of 4.1 dB.

• Journal of information and communication convergence engineering
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• v.11 no.3
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• pp.147-152
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• 2013

A novel balun being the structure of a Wilkinson power divider is suggested and fabricated. One of the power dividing paths in the suggested balun uses a conventional ${\lambda}/4$ transmission line for $-90^{\circ}$ phase shifting, and the other path uses a composite right/left-handed -${\lambda}/4$ transmission line for $+90^{\circ}$ phase shifting with four series capacitors and three parallel inductors. In addition, the suggested balun uses two $50-{\Omega}$ resistors and a conventional $50-{\Omega}$ transmission line of ${\lambda}/2$ electrical length between the two output ports, achieving good isolation and reflection values of two balanced ports. The suggested balun is simulated by the advanced design system simulation program and fabricated on TLX-9 20-mil substrate. The fabricated balun has a very good values of $S_{11}$ = -27.46 dB, $S_{21}$ = -3.40 dB, and $S_{31}$ = -3.28 dB, a phase difference of $-179.5^{\circ}$, a magnitude difference of 0.12 dB, and a delay difference of 0.1 ns, with $S_{22}$ = -36.28 dB, $S_{33}$ = -27.19 dB, and $S_{32}$ = -25.2 dB at 1 GHz, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2462-2467
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• 2009

This paper proposes a dual band branch line coupler (BLC) using a composite right/left handed (CRLH) transmission line. The existing dual band BLCs with open stubs require hundreds of line impedance for the open stub as the frequency bands approach to each other, so it has been almost impossible to realize them. However in the proposed BLC, a CRLH transmission line replaces the open stub with an extremely high line impedance so that the BLC circuit may be realized even two frequencies are close to each other. As an example, a dual band BLC operating at 1800MHz and 2300MHz (the frequency ratio is 1:1.28) is designed and measured. Open stubs with $560\Omega$ line impedance are replaced by CRLH transmission lines for realizing the dual band BLC. The measured performances prove that the dual band operation is well acceptable and the proposed design method is successful even the ratio between two frequencies is not around two nor more.

• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.84-89
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• 2017

This paper presents a dual-wideband bandpass filter (BPF) with high band-to-band isolation and skirt selectivity using distributed composite right/left-handed (CRLH) transmission line (TL) quad-mode resonators (QMRs). The results of the proposed distributed CRLH TL unit cell analysis are used to establish the scattering parameters and the resonance frequencies of the QMR constituting the dual-wideband BPF. A novel dual-wideband bandpass filter is designed and fabricated, using the derived scattering characteristics. The measured results show that the fabricated dual-wideband bandpass filter has an insertion loss of less than 1.08dB in the lower band, and of 2.01dB in the upper band, a bandwidth of 2.8-5.52GHz and 9.68-12.26GHz, and a band-to-band isolation of more than 38dB, from 6.34-8.42GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1042-1047
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• 2012

In order to obtain balanced ports matching and isolation between balanced ports of a Marchand balun, a compact isolation network is proposed. The proposed compact isolation network is designed using composite right/left-hand (CRLH) transmission line and compact phase inverter using CRLH transmission line unit cell. Also, design method and analysis of proposed isolation network are presented. The sizes of the proposed isolation networks are significantly reduced to $0.11{\lambda}_g$ and $0.07{\lambda}_g$ compared with the conventional isolation network of $0.5{\lambda}_g$. The Marchand balun is operated at 2.45 GHz and is demonstrated through excellent experimental results.

• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.399-405
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• 2009

This paper proposes a design of attenuator based on meta-material structure and its application. The unit-cell attenuator based on the lossy transmission line consists of the CRLH(Composite Right/Left Handed) transmission line and PIN diodes to be controlled internal loss according to diode bias voltage to change resistance of diode. Also, to reduce the initial losses, there is used parallel connection of PIN diodes. To increase attenuations, it is connected a cascade unit-cell of attenuator with periodic structure. The attenuation quantities of unit-cell are about 10dB and phase variations are 15o maximum at 1.5 GHz ~ 2.5 GHz. Also, its application is represented a vector modulator.