• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.903-906
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• 2008

We developed the advanced LTPS (A-LTPS) manufacturing process. The a-Si TFT process was combined with selectively enlarging laser crystallization (SELAX) technology to improve the carrier mobility in the region where the peripheral circuits are to be fabricated. A 2.4-inch IPS-pro LCD panel for personal digital assistant use was successfully fabricated using the developed technology.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.177-180
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• 1999

A two-stage monolithic microwave integrated circuits (MMIC) broad-band power amplifier with AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (PHEMT) has been developed for the up-link and down-link applications for local multipoint distribution systems (LMDS) in the frequency range of 24~28㎓. The amplifier has a small signal gain of 18.6㏈ at 24.5㎓ and 16.7㏈ at 27.1㎓. It achieved output powers of 19.8㏈m with PAE of 19.8% at 24.5㎓ and 18.8㏈m at 27.1㎓.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.237-242
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• 2008

A number of wireless technologies have been implemented, but each technology has its limitation in terms of coverage and bandwidth. WLAN and 3G cellular network has emerged to be a complementary platform for wireless data communications. However, the mobility of roaming terminals in heterogeneous networks poses several risks. To maintain secure communications in universal roaming, the effective authentication must be implemented. The focus of this paper is on analysis of authentication architecture involved in integrated WLAN/3G networks.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.307-309
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• 2005

본 논문에서는 distance-vector 기반의 라우팅 알고리즘에 경로 지속성에 대한 분석을 적용한 Durable Distance Vector Multicast(DDVM) 알고리즘을 제안한다. DDVM은 기존의 distance vector 알고리즘에 PATHS의 분석 내용을 기반으로 한 경로 지속성 정보를 포함하여 견고한 멀티캐스팅 경로를 구성한다. 또한 경로 정보에 목적지까지의 세부적인 경로의 지속성 정보 역시 포함하여 멀티캐스팅 경로 형성의 실패율을 줄이고 보다 지속성 있는 경로를 멀티캐스팅 경로에 포함시킨다. 이러한 경로들을 통해 멀티캐스팅을 수행함으로서 high mobility 환경에서 기존의 알고리즘보다 높은 전송율을 보이며, 실험 결과를 통해 이를 확인할 수 있다.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1027-1029
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• 2004

In this paper, we have fabricated pentacene thin film transistors (TFTs) using polyvinylphenol (PVP) copolymer and cross-linked PVP as gate insulator on glass and plastic (PET) substrate. Depending on the density of PVP and cross-link material the performance has been changed. We obtained the best device performance with the mobility of 0.32cm2/V${\cdot}$sec and the on/off current ratio of 1.19${\times}$106 for the case of 10wt% PVP copolymer mixed with 5wt% poly (melamine-co-formaldehyde). Additionally using pentacene TFTs with the above PVP gate insulator, we fabricated the integrated circuits including inverter which produced the gain of 9.7.

• ETRI Journal
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• v.33 no.1
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• pp.13-17
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• 2011

A highly miniaturized on-chip $180^{\circ}$ hybrid employing periodic ground strip structure (PGSS) was realized on a silicon radio frequency integrated circuit. The PGSS was placed at the interface between $SiO_2$ film and silicon substrate, and it was electrically connected to top-side ground planes through the contacts. Owing to the short wavelength characteristic of the transmission line employing the PGSS, the on-chip $180^{\circ}$ hybrid was highly miniaturized. Concretely, the on-chip $180^{\circ}$ hybrid exhibited good radio frequency performances from 37 GHz to 55 GHz, and it was 0.325 $mm^2$, which is 19.3% of a conventional $180^{\circ}$ hybrid. The miniaturization technique proposed in this work can be also used in other fields including compound semiconducting devices, such as high electron mobility transistors, diamond field effect transistors, and light emitting diodes.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1680-1682
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• 2007

The integrated circuits such as inverters, ring oscillators, NAND and NOR gates, and rectifiers were fabricated on PEN substrate by using pentacene TFTs. The OTFTs used bottom contact structure and produced the average mobility of $0.26\;cm^2/V.sec$ and on/off current ratio of $10^5$. All circuits worked successfully like the simulation results. Especially, the rectifier was able to operate up to 1 MHz input signals, and ring oscillator exhibited oscillation frequency of 1MHz at-40V.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.443-445
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• 2008

We have fabricated vertical type organic thin film transistor using $C_{60}$ as a n-type active material to improve the problems of conventional OTFTs. In general, it can be argued that the characteristics of organic transistor were influenced by carrier mobility and density. We have used several kinds of metals as source and gate electrodes to optimize the device characteristics using $C_{60}$. In addition, we have examined the feasibility of fabrication of organic light-emitting transistor (OLET) using MEH-PPV as an emission layer.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.408-408
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• 2014

Graphene has received attention with its high electron mobility and visual transparency as a promising material for optoelectronic and photonic applications. Combination of graphene and conducting nanostructures i.e. plasmonic structures has recently been researched for enhancing light-matter interaction and overcoming diffraction limit of light. Here we show enhanced photodetection of incoherent visible light with graphene-mediated plasmonics. Gold nanoparticles fabricated by focused ion beam was used as an active element of photodetection and graphene was utilized as an interfacing material between nanostructures and electrodes. Hot electrons generated upon plasmon decay within nanoparticles pass over the potential barrier between nanostructure and graphene and give rise to a photocurrent with built-in electric field. We report 76.7% enhancement of photocurrent under resonant irradiation of fiber-coupled halogen lamp compared to the case without light illumination. We showed wavelength-dependent current response arisen from plasmonic nanostructure, providing a good agreement with theoretical calculation.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.342-345
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• 2014

An active frequency doubler monolithic microwave integrated circuit (MMIC) for E-band transceiver applications is presented in this letter. This MMIC has been fabricated in a commercial $0.1-{\mu}m$ GaAs pseudomorphic high electron mobility transistor (pHEMT) process on a 2-mil thick substrate wafer. The fabricated MMIC chip has been measured to have a high output power performance of over 13 dBm with a high fundamental leakage suppression of more than 38 dBc in the frequency range of 71 to 86 GHz under an input signal condition of 10 dBm. A microstrip coupled line is used at the output circuit of the doubler section to implement impedance matching and simultaneously enhance the fundamental leakage suppression. The fabricated chip is has a size of $2.5mm{\times}1.2mm$.