• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 제13회 정기총회 및 2002년도 동계학술발표회
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• pp.178-179
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• 2002

We generate optical millimeter-waves by double-sideband suppressed carrier (DSB-SC) modulation using a Mach-Zehnder (MZ) modulator biased at the minimum power. The DSB-SC modulation allows the high-frequency intensity modulation for millimeter-wave generation at the twice of the MZ modulator driving frequency.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.53-56
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• 2001

This paper has been developed a millimeter-wave radar to prevent car collision. This system needs to progress the problem as follows; (1) Increase of traffic accidents causing damage and injuries due to the increased number of motor vehicles and long distance driving, (2) Need for a device to help drivers who are in trouble due to bad weather conditions. (3) Need for a millimeter-wave radar as obstacles which need to be detected are small. This system is composited with some major technologies, Narrow beams to recognize obstacles or other objects, One-side circuit technology to prevent interference between electric waves, and Parts designed for radar products which are able to transmit millimeter - waves. The system has a various a application Field, Car distance auto-control system, prevent bump collision due to unexpected stoppage of the front car or careless driving, obstacle warning system, Car following system, and industrial and military purposes system. We have a looking forward to propose to develop field tests under various road conditions and hybrid car sensor by combining with other sensors

• 전자통신동향분석
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• 제37권2호
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• pp.11-20
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• 2022

Terahertz electromagnetic waves are considered the waves for the next generation of security checking technology. They can penetrate opaque materials, such as plastics, fibers, papers, and leathers. In addition, they are harmless to humans they cannot penetrate human skins. Moreover, because their frequencies are higher than those of millimeter waves, higher resolution and more detailed information is expected than the millimeter wave-based technologies In this study, we describe the trends and prospectives of terahertz technology as security checking technology that can be directly applied to a human body.

• 광학과기술
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• 제5권1호
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• pp.5-10
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• 2001

• 한국정보통신학회논문지
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• 제10권1호
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• pp.164-170
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• 2006

밀리미터파는 고해상도의 거리 및 영상정보를 얻기 위하여 매우 유용하게 쓰여 질 수 있다. 또한 고속 멀티미디어 서비스의 필요성이 갈수록 커지고 상대적으로 낮은 주파수 대역의 주파수 자원이 부족하기 때문에 밀리미터파를 이용한 광대역 통신시스템에서의 실용화를 위하여 많은 연구가 진행되고 있다. 그러나 이러한 밀리미터파 시스템의 성능을 제대로 평가하기 위해서는 우선 대기 중에서의 밀리미터파의 전파특성에 대한 분석이 선행되어져야 한다. 전계에 의한 강도 변화정도와 MCF(Mutual coherence function)는 밀리미터파 전파에 있어서의 대기에 의한 영향을 표시하게 된다. 본 논문에서는 밀리미터파 전파특성을 분석하기 위하여 QOM(Quasi-optical method) 방법을 적용하여 안테나 초점평면에서의 전계에 의한 강도 분포로부터 MCF를 얻을 수 있는 기법을 고찰하였다. 아울러 효과적인 측정 및 분석을 위하여 전계에 의한 강도 대신 안테나 초점평면에서의 플럭스(flux)측정을 통하여 MCF를 구할 수 있는 방법을 제안하였다.

• ETRI Journal
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• 제38권6호
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• pp.1052-1063
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• 2016

We propose a millimeter wave (MMW)-based mobile hotspot network (MHN) system for application in high-speed railways that is capable of supporting a peak backhaul link throughput of 1 Gbps per train at 400 km/h. The MHN system can be implemented in subways and high-speed trains to support passengers with smart devices and provide access to the Internet. The proposed system can overcome the inherent high path loss in MMW through system designs and high antenna gains. We present a simulation of the system performance that shows that a fixed beamforming strategy can provide high signal-to-interference-plus-noise-ratio similar to those of an adaptive beamforming strategy, with the exception of 15% of the train path in which the network can use link adaptation with low-order modulation formats or trigger a handover to maintain the connection. We also demonstrate the feasibility of the MHN system using a test bed deployed in Seoul subway line 8. The backhaul link throughput varies instantaneously between 200 Mbps and 500 Mbps depending on the SNR variations while the train is running. During the field trial, the smartphones used could make connections through offloading.

• 한국전자파학회지:전자파기술
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• 제19권5호
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• pp.13-18
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• 2008

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.1009-1012
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• 2000

In this paper, we have designed and fabricated power PHEMT’s with an unit gate width of 80$\mu\textrm{m}$ and 4 fingers, and MIMIC power amplifiers using the PHEMT’s as well. The PHEMT’s have a 0.2$\mu\textrm{m}$ gate length and source to drain spacing of 3$\mu\textrm{m}$. The characteristics of the fabricated PHEMT’s are 4.08dB of S$\sub$21/ gain at the 35GHz and 317mS/mm of gm, and 62GHz of f$\sub$T/ and 120GHz of f$\sub$max/. The designed and fabricated MIMIC’s power amplifiers with 6 PHEMT’s and MIN capacitors were fully passivated by 1000 Α of Si$_3$N$_4$ film for higher performance and surface protects. The chips were processed using the MINT processes, and size was 3.25 ${\times}$ 1.8$\textrm{mm}^2$. The fabricated MIMIC power amplifiers have RF characteristics such as 11.25dB of S$\sub$21/ gain, 11.37dB of input return-loss and 12.69dB of output return-loss at the 34.55GHz.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.243-244
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• 2022

In this paper, experiments were conducted on signal amplification of polymer capsules for application to Ground Penetrating Radar so as to enable real-time monitoring of polymer capsules inside concrete using the Morphology Dependent Resonance phenomenon. A TEM CELL and a vector network analyzer were used to analyze the difference in resonance frequency depending on the material of the sphere and the presence or absence of fracture. In order to manufacture a capsule of a size that can be measured using millimeter waves used in GPR, we manufactured a capsule with a 3D printer and analyzed the effects of the presence or absence of coating and the size of the capsule on the resonance frequency. Resonant frequency or signal amplification is more affected by diameter than coating. The capsule showing the highest amplification is the resin-coated 50 mm diameter capsule with a 316-fold increase and the lowest capsule is the uncoated 10 mm diameter capsule with a signal amplification of 11.9 times. These results demonstrate the potential of GPR to measure the position and state of self-healing capsules, which are small-sized polymers, in real time using millimeter waves.

• ETRI Journal
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• 제40권3호
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• pp.389-395
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• 2018

A novel class of planar metamaterial unit-cells consisting of a peace logo pattern is presented. A significant advantage of the proposed peace-logo planar metamaterial (PLPM) unit-cell over existing designs is its tunability, simplicity, and compatibility with microstrip structures. The theoretical analysis is founded on the famous transmission-line theory for the metamaterial concept. Then, the tunable dual-band two-sided PLPM (TSPLPM) unit-cell is designed by printing a similar PLPM pattern at the bottom of the substrate. The influence of the bottom PLPM pattern on the resonance frequencies of the unit-cell was analyzed by performing numerical simulations using CST Microwave Studio 2017 and HFSSv15 simulators. The results of the numerical simulations demonstrated that the proposed TSPLPM has the ability to control the resonance frequencies over 50 GHz-75 GHz for millimeter-wave applications.