• 한국항행학회논문지
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• 제17권5호
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• pp.491-496
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• 2013

본 논문에서는 보안등의 통합 모니터링과 제어를 위한 3G 이동통신용 RF모듈에 적용 가능한 반파장 폴디드 슬롯 안테나를 제안하였다. 제안된 안테나는 입력임피던스가 $50{\Omega}$에 가까운 총 길이가 ${\lambda}g$인 전형적인 폴디드 슬롯 안테나의 장점을 유지하면서 절반의 크기를 가지고 PCB의 가장자리에 위치할 수 있도록 변형된 폴디드 슬롯 구조이다. 제안된 안테나는 국내 3G 이동통신 대역용으로, $40.5{\times}62mm^2$의 기판 중 상단 $40.5{\times}10mm^2$의 공간을 이용하여 설계 및 제작하였다. 제작된 안테나를 측정한 결과, 390 MHz의 대역폭, 2 dBi의 이득을 얻을 수 있었다.

• 한국재료학회지
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• 제29권1호
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• pp.37-42
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• 2019

This study investigates Ag coated $Cu_2O$ nanoparticles that are produced with a changing molar ratio of Ag and $Cu_2O$. The results of XRD analysis reveal that each nanoparticle has a diffraction pattern peculiar to Ag and $Cu_2O$ determination, and SEM image analysis confirms that Ag is partially coated on the surface of $Cu_2O$ nanoparticles. The conductive paste with Ag coated $Cu_2O$ nanoparticles approaches the specific resistance of $6.4{\Omega}{\cdot}cm$ for silver paste(SP) as $(Ag)/(Cu_2O)$ the molar ratio increases. The paste(containing 70 % content and average a 100 nm particle size for the silver nanoparticles) for commercial use for mounting with a fine line width of $100{\mu}m$ or less has a surface resistance of 5 to $20{\mu}{\Omega}{\cdot}cm$, while in this research an Ag coated $Cu_2O$ paste has a larger surface resistance, which is disadvantageous. Its performance deteriorates as a material required for application of a fine line width electrode for a touch panel. A touch panel module that utilizes a nano imprinting technique of $10{\mu}m$ or less is expected to be used as an electrode material for electric and electronic parts where large precision(mounting with fine line width) is not required.

• 한국전기전자재료학회논문지
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• 제31권5호
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• pp.295-299
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• 2018

In this work, we conducted a study on cell strings of high efficiency and high power solar cell modules via simulation. In contrast to the conventional module manufacturing method, the simulation was performed by connecting cutting cells divided into four parts from 6-in size using the electrically conductive adhesive (ECA). The resistance of the ECA added in series connection was extracted using an experimental method. This resistance was found to be $3m{\Omega}$. Based on this simulation, we verified the change in efficiency of the string as a function of the number of cutting cell connections. Consequently, the cutting cell efficiency of the first 20.08% was significantly increased to 20.63% until the fifth connection; however, for further connections, it was confirmed that the efficiency was saturated to 20.8%. Connecting cutting cells using ECA improves the efficiency of the string; therefore, it is expected that it will be possible to fabricate modules with high efficiency and high power.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.88.1-88.1
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• 2015

In recent printed electronics technology, Photo-Sintering, a technique for sintering materials using a light source, has attracted attention as an alternative to time-consuming high-temperature thermal processes. The key principle of this technique is the selective heating of a strongly absorbent thin film, while preventing the heating of the transparent substrate by the light source. Many recent studies have used a flash lamp as the light source, and investigated the material-dependent effect of the width or intensity of the pulsed light. However, the flash lamp for sintering is not suitable for industry yet, because of needing too high power to sinter for a large scale. In energy-saving and large-scale sintering, LED technologies would be very useful in the near future. In this work, we investigated a sintering process for silver nanoparticles using UV-LED array. Silver nanoparticles in ink were inkjet-printed on a $1{\times}1cm$ area of a PET film and photo-sintered by 365 nm UV-LED module. A sheet resistance value as low as $72.6m{\Omega}/sq$ (2.3 - 4.5 times that of bulk silver) was obtained from the UV-LED sintering at 300 mW/cm2 for 50 min.

• 전자공학회논문지D
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• 제35D권10호
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• pp.91-97
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• 1998

10 Gbps용 전계 흡수형 InGaAsP/InGaAsP 응력 완화 MQW (Multiple Quantum Well) 광변조기의 변조 성능은 패키징후 발생되는 기생 특성에 의해서 큰 영향을 받음을 확인하였다. 이 초고주파 기생 특성은 변조기의 변조 대역폭을 제한하고 처핑 변수를 증가시키는 요인이 된다. 따라서, 이러한 기생 성분중 고속·광대역 변조시 변조 성능을 크게 저하시키는 본딩와이어에 의한 유도성 기생성분을 최소화시키기 위해 유전체 몰딩된 이중 본딩와이어 구조를 제안하였다. 50 Ω 저항으로 병렬 종단된 MQW 광변조기에 제안된 본 구조를 이용할 경우, 패키징전에 비하여 변조 대역폭이 약 125 %가 확대됨을 확인하였다. 또한 이 구조를 이용할 경우 기존에 무시되었던 패키징 기생 특성에 의한 처핑 변수의 영향을 최소화시킬 수 있는 효과적인 방법이 됨을 확인하였다. 본 연구 결과는 10 Gbps 대역 이상의 초고속 외부 광변조기의 변조 성능 극대화를 위한 최적 패키지 구현 자료로서 유용하게 사용될 수 있다.

• 전기학회논문지
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• 제65권5호
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• pp.862-867
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• 2016

In this study, the embroidery textile conductive wire of conductive yarn was designed into the wearable integrated clothing for sensing the infant's body temperature. To develop a high quality of the stable fiber-based textile conductive wire, firstly the five types of conductive yarns were twisted or covering polyester yarns and the coated conductive fiber with silver(Ag) or iron(Fe). As a result of comparative conductivity in conductive yarns of yarn processing, the 250 denier of conductive yarns with $0.74{\Omega}$/1~5cm were proposed and used for the integrated embroidery textile conductive wire for sensing. During experiments using the proposed embroidery textile conductive wire, measured resistance of thermistor according to the body temperature was correctly delivered to amplifier module, and showed feasible reliability of temperature sensing. As a wearable application, conductive yarns which takes forms of embroidery textile conductive wire would seems to be reliable as a conductive wire and could be replaced by the conductive metal wires.

• 한국전기전자재료학회논문지
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• 제26권1호
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• pp.38-43
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• 2013

In this study we aims to examine the effects of $Co_3O_4$ and NiO doping on the defects and electrical properties in ZnO-$Bi_2O_3-Sb_2O_3$ (Sb/Bi=0.5) varistors. It seemed to form ${Zn_i}^{{\cdot}{\cdot}}$(0.20 eV) and ${V_o}^{\cdot}$(0.33 eV) as dominant defects in Co and Ni co-doped ZBS system, however only ${V_o}^{\cdot}$ appeared in Co- or Ni-doped ZBS. Even though the same defects it was different in capacitance (1.5~4.5 nF) and resistance ($0.3{\sim}9.5k{\Omega}$). The varistor characteristics were improved with Co and Co+Ni doping (non-linear coefficient, ${\alpha}$= 36 and 29, relatively) in ZBS. The various parameters ($N_d=1.43{\sim}2.33{\times}10^{17}cm^{-3}$, $N_t=1.40{\sim}2.28{\times}10^{12}cm^{-2}$, ${\Phi}b$=1.76~2.37 V, W= 98~118 nm) calculated from the C-V characteristics in our systems did not depend greatly on the type of dopant, which were in the range of a typical ZnO varistors. It should be derived a improved C-V equation carefully for more reliable parameters because the variation of the varistor capacitance as a function of the applied dc voltage is depend on the defect, frequency, and temperature.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1638-1643
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• 2018

Multi-layer ceramic capacitors as decoupling capacitor were fabricated by dielectric composition with a high dielectric constant. The fabricated decoupling capacitors were embedded in the PCB of the 10G RF transceiver module and evaluated for the characteristics of electrical noise by the level of AC input voltage. In order to further improve the electrical properties of the $BaTiO_3$ based composite, glass frit, MgO, $Y_2O_3$, $Mn_3O$, $V_2O_5$, $BaCO_3$, $SiO_2$, and $Al_2O_3$ were used as additives. The electrical properties of the composites were determined by various amounts of additives and optimum sintering temperature. As a result of the optimized composite, it was possible to obtain a density of $5.77g/cm^3$, a dielectric constant of 1994, and an insulation resistance of $2.91{\times}10^{12}{\Omega}$ at an additive content of 5wt% and a sintering temperature of $1250^{\circ}C$. After forming a $2.5{\mu}m$ green sheet using the doctor blade method, a total of 77 layers were laminated and sintered at $1180^{\circ}C$. A decoupling capacitor with a size of $0.6mm(W){\times}0.3mm(L){\times}0.3mm(T)$ (width, length and thickness, respectively) and a capacitance of 100 nF was embedded using a PCB process for the 10G RF Transceiver modules. In the range of AC input voltage 400mmV @ 500kHz to 2200mV @ 900kHz, the embedded 10G RF Transceiver modules evaluated that it has better electrical performance than the non-embedded modules.

• 대한기계학회논문집A
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• 제36권5호
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• pp.475-479
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• 2012

본 논문은 고차가지구조 폴리머인 AEO3000 를 이용한 UV 광경화 성형 공정을 제안하고자 한다. 이는 기존의 바이오칩 제작에 사용되는 PDMS 보다 경도가 높아 금속 전극 형성이 용이하고 제작 공정이 빠르다는 장점을 갖는다. AEO3000 을 이용하여 본 연구에서는 4 개의 소자를 전기적 유체적으로 연결할 수 있는 전기유체 통합벤치를 제작하고 미소유체 혼합소자와 세포분리소자를 연결, 본 소재와 공정이 바이오칩에 적용될 수 있음을 검증하였다. 전기 유체적 특성 분석 결과 전기적 접촉 저항은 $0.75{\pm}0.44{\Omega}$으로 충분히 작은 값을 보였으며, 유체 접속의 압력 저하는 8.3kPa로 기존의 튜브 연결 방법 대비 39.3% 개선된 값을 보였다. 통합벤치에 접속된 소자에 활성 및 비활성 효모를 주입하여 순차적인 혼합 및 재분리를 성공적으로 구현함으로써 본 소자에 적용된 AEO3000 및 UV 광경화 공정이 생체시료의 처리에 적용될 수 있음을 실험적으로 검증하였다. 이는 바이오 의료 분야에 적용 가능한 생체 친화적 소재의 고속 생산에 응용될 수 있다.

• 한국전기전자재료학회논문지
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• 제25권12호
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• pp.943-948
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• 2012

A new water energy harvester module, which is composed of piezoelectric bimorph cantilevers, harvesting circuit and a shaft with 16 impellers at a center axis, was fabricated for energy harvesting application. High energy density $Pb(Zr_{0.54}Ti_{0.46})O_3$ + 0.2 wt% $Cr_2O_3$ + 1.0 wt% $Nb_2O_5$ (PZT-CN) thick film obtained by tape casting method was used for the bimorph cantilever. The PZT-CN bimorph cantilever with a proof mass of 49 g exhibited extremely high output power of 22.5 mW (24 $mW//cm^3$) at resonance frequency of 11 Hz. In addition, the fabricated water energy harvester has a cylindrical structure with 48 bimorph cantilevers clamped at inner surface. A significantly high output power of 433 mW was obtained at a rotation speed of 120 rpm with a resistive load of $500{\Omega}$ for the water energy harvester.