• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.716-722
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• 2017

In this paper, a fully printed NFC tag operating at 13.56 MHz was designed and fabricated using silver nano-paste and carbon ink. The proposed NFC tag has a printed coil with an inductance of $2.74{\mu}H$ on a PI film for application to an NFC tag IC with an internal capacitance of 50 pF. Screen printing technology used in this paper has advantages such as large area printing for mass production, low cost and eco-friendly process compared to conventional PCB manufacturing process. The proposed structure consists of a circular coil implemented as a single layer using silver nano-paste and carbon ink, a jumper pattern for chip mounting between the outer edge and the center of the coil, and an insulation pattern between the coil and the jumper pattern. In order to verify the performance of the proposed NFC tag, we performed the measurements of the printing line width, thickness, line resistance, adhesion and environmental reliability, and confirmed the suitability of the NFC tag based on the full-printed manufacturing method.

• Korean Journal of Materials Research
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• v.10 no.12
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• pp.807-811
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• 2000

CeO$_2$ and SrBi$_2$Ta$_2$O$_{9}$ (SBT) thin films for MFISFET (Metal-ferroelectric-insulator-semiconductor-field effect transistor) were deposited by r.f. sputtering and pulsed laser ablation method, respectively. The effects of sputtering gas ratio(Ar:O$_2$) during deposition for CeO$_2$ films were investigated. The CeO$_2$ thin films deposited on Si(100) substrate at $600^{\circ}C$ exhibited (200) preferred orientation. The preferred orientation, Brain size and surface roughness of films decreased with increasing oxygen to argon gas ratio. The films deposited under the condition of Ar:O$_2$= 1 : 1 showed the best C- V characteristics. The leakage current of films showed the order of 10$^{-7}$ ~10$^{-8}$ A at 100kV/cm. The SBT thin films on CeO$_2$/Si substrate showed dense microstructure of polycrystalline phase. From the C-V characteristics of MFIS structure with SBT film annealed at 80$0^{\circ}C$, the memory window width was 0.9V at 5V The leakage current density of Pt/SBT/CeO$_2$/Si structure annealed at 80$0^{\circ}C$ was 4$\times$10$^{-7}$ /$\textrm{cm}^2$ at 5V.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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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.

• Journal of Sensor Science and Technology
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• v.6 no.5
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• pp.400-406
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• 1997

The electrical and physical characteristics of aluminum oxide and Pt thin films on it, deposited by reactive sputtering and DC magnetron sputtering, respectively, were analyzed with increasing annealing temperature($400{\sim}800^{\circ}C$) by four point probe, SEM and XRD. Under $600^{\circ}C$ of annealing temperature, aluminum oxide had the properties of improving Pt adhesion to $SiO_{2}$ and insulation without chemical reaction to Pt thin films and the resistivity of Pt thin films was improved. But these properties of aluminum oxide and Pt thin films on it were degraded over $700^{\circ}C$ of annealing temperature because aluminum oxide was changed into metal aluminum and then reacted to Pt thin films deposited on it. The thermal characteristics of Pt micro heater were analyzed with Pt-RTD integrated on the same substrate. In the analysis of properties of Pt micro heater, active area was smaller size, Pt micro heater had better thermal characteristics. The temperature of Pt micro heater with active area, $200{\mu}m{\times}200{\mu}m$ was up to $400^{\circ}C$ with 1.5watts of the heating power.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.429-429
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• 2007

For various applications of liquid crystal displays (LCDs), the uniform alignment of liquid crystal (LC) molecules on treated surfaces is significantly important. Generally, a rubbing method has been widely used to align the LC molecules on polyimide (PI) surfaces. Rubbed PI surfaces have suitable characteristics, such as uniform alignment. However, the rubbing method has some drawbacks, such as the generation of electrostatic charges and the creation of contaminating particles. Thus, we strongly recommend a non contact alignment technique for future generations of large high-resolution LCDs. Most recently, the LC aligning capabilities achieved by ultraviolet and ion-beam exposures which are non contact methods, on diamond-like carbon (DLC) inorganic thin film layers have been successfully studied because DLC thin films have a high mechanical hardness, a high electrical resistivity, optical transparency, and chemical inertness. In addition, nitrogen-doped DLC (NDLC) thin films exhibit properties similar to those of the DLC thin films and a higher thermal stability than the DLC thin films because C:N bonding in the NDLC thin filmsis stronger against thermal stress than C:H bonding in the DLC thin films. Our research group has already studied the NDLC thin films by an ion-beam alignment method. The $SiN_x$ thin films deposited by plasma-enhanced chemical vapor deposition are widely used as an insulation layer for a thin film transistor, which has characteristics similar to those of DLC inorganic thin films. Therefore, in this paper, we report on LC alignment effects and pretilt angle generation on a $SiN_x$, thin film treated by ion-beam irradiation for various N ratios

• Journal of the Korean GEO-environmental Society
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• v.17 no.5
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• pp.37-46
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• 2016

In order to determine the variability of environmental characteristics of lightweight air-foamed soil using marine clay according to freezing-thawing and soaking conditions, unconfined compressive strength of the lightweight air-foamed soil samples made by changing the amount of cement under curing conditions of outdoor low temperature, underground or indoor wetting were observed. Compressive strength was not increased under freezing-thawing (temperature range of $-9.1^{\circ}C{\sim}17.2^{\circ}C$) regardless of the amount of cement but the more cement using, it was increased rapidly by underground curing conditions within 30 cm beneath ground level. Therefore, it is necessary to install insulation layer cutting off exterior cold air after construction of lightweight air-foamed soil in condition of freezing-thawing. Bulk density was increased too small under the long-time soaking condition, it tended to decrease rapidly when samples were dried up and had below 6% of water contents. But variability of compressive strength and bulk density was very small for preventing drying and keeping its wet state. The lightweight air-foamed soil that installed beneath ground water level or covered by soil can be evaluated as a long-term reliable construction material.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.428-439
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• 2020

This study was carried out to investigate the effect of PO film on the increase of crop yield and energy saving through PO and PE film greenhouse application and comparison test. As a experimental greenhouse, two single span greenhouses (1-1 W) and two double span greenhouses (1-2 W) were used. During winter season, PO film (0.15 mm outer layer, 0.10mm inner layer) was used as a covering material of greenhouse in double layers for double-span (B15) and single-span(B21), and PE film used for double-span (B15), and single-span (B23) as a control. The experimental vegetable was tomato(Solanum lycopersicum L.) cultivated in soil and the cultivar of that was 'Happiness'. That was cultivated from December 3, 2019 to April 30, 2020. The temperature at night inside the greenhouse was maintained at 15℃, and the side and roof windows were opened to maintain 23 ~ 24℃ during the day. As a result, this study showed that the yield in single-span greenhouse(B21) covered with a PO film increased 20% and that in double-span greenhouse (B16) increased by 9% compared to the greenhouse covered with a PE film (B23, B15). Fuel consumption of the single-span greenhouse (B21) with the cover of PO film was reduced by 12.4% and that of double-span greenhouse was done by 11.5% compared to that of the PE film greenhouse (B23, B15) without any difference between them in growing state.