• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1639-1645
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• 2015

In UHD high-speed video transmission system, when a signal within certain frequency region coincides electrically and structurally, the system becomes unstable because the energy is concentrated, and signal flux is interfered and distorted. For the instability, power integrity analysis should be conducted. To remove the signal distortion for MLB, using a high-frequency design technique for EMI phenomenon, EMI which radiates electromagnetic energy fluxed into power layer was analyzed considering system stabilization. In this paper, we proposed an adaptive MLB design method which minimizes high-frequency noise in MLB structure, enhances signal integrity and power integrity, and suppresses EMI. The characteristic impedance for multi-layer circuit board proposed in this study were High-Speed Video Differential Signaling(HSVDS) line width w = 0.203, line gap d = 0.203, beta layer height h = 0.145, line thickness t = 0.0175, dielectric constant ε_r = 4.3, and characteristic impedance Zdiff = 100.186Ω. When high-speed video differential signal interface board was tested with optimized parameters, the magnitude of Eye diagram output was 672mV, jittering was 6.593ps, transmission frequency was 1.322GHz, signal to noise was 29.62dB showing transmission quality improvement of 10dB compared to previous system.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1129-1132
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• 1995

In the preparation of the layered $BaTiO_3$ thin films with high performance, the new stacking method using the continuous cooling of the substrate was introduced. Amorphous/polycrystalline $BaTiO_3$ layered structure was confirmed by SEM and index of refraction. The layered $BaTiO_3$ thin films formed by the new stacking method showed such a high dielectric constant that the layered structure could not be explained by a stacking structure of the two defined layers but could only be explained by multi-layered structure, i.e. amorphous/micro crystalline/polycrystalline structure. The layered $BaTiO_3$ thin film with a thickness of 240 nm showed higher capacitance per unit area and breakdown strength than the double layered $BaTiO_3$ thin film prepared by the conventional stacking method. And well defined ferroelectric hysteresis leer was observed in the layered $BaTiO_3$ thin film with a thickness of 200 nm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.499-503
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• 2002

In this study, to develop the high power piezoelectric transformer for adaptor, PSN-PNN-PZT system ceramics were formulated as a function of $MnO_2$ addition and its dielectric and piezoelectric characteristics were investigated. Multi-layer piezoelectric transformer using an excellent composition was also fabricated and its electrical properties evaluated. The composition ceramics added to 0.5wt%$MnO_2$ showed the maximum value of $k_p=0.61$ and $Q_m=1.321$. As the output power of piezoelectric transformer is increased, its temperature rise increased. At the fixed 18W output power, the transformer was stably operated.

• Journal of electromagnetic engineering and science
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• v.8 no.3
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• pp.129-133
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• 2008

An integrated passive device(IPD) technology by semi-insulating(SI)-GaAs-based fabrication has been developed to meet the ever increasing needs of size and cost reduction in wireless applications. This technology includes reliable NiCr thin film resistor, thick plated Cu/Au metal process to reduce resistive loss, high breakdown voltage metal-insulator-metal(MIM) capacitor due to a thinner dielectric thickness, lowest parasitic effect by multi air-bridged metal layers, air-bridges for inductor underpass and capacitor pick-up, and low chip cost by only 6 process layers. This paper presents the Wilkinson power divider with excellent performance for digital cellular system(DCS). The insertion loss of this power divider is - 0.43 dB and the port isolation greater than - 22 dB over the entire band. Return loss in input and output ports are - 23.4 dB and - 25.4 dB, respectively. The Wilkinson power divider based on SI-GaAs substrates is designed within die size of $1.42\;mm^2$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.6
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• pp.458-463
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• 2010

MLCC (multi-layer ceramic capacitor) is usually fabricated by lamination of predetermined number of single layers. Often, the state of MLCC before sintering is called the green state, whose strength comes from the adhesion between the dielectric material and the polymer binder. Therefore the lamination of a single layer before sintering can be easily deformed by environment due to the relatively lower strength. After the compression process, which helps single sheets cohereto with adjacent sheets, the MLCC green bar is preheated to resolve the probable internal stress. Unfortunately, unexpected deformation after preheating resulted in problems during cutting of the MLCC green bar. In this study, one of 2 primary hypotheses which were proposed to resolve the unexpected deformation after preheating was examined by quantitative experiment with GC/MS (gas chromatograpy/mass spectrometer). The proportion of deformation caused by DOP evaporation, which was primarily evaporated componet during preheating, to the total deformation of the MLCC green bar was found to be 53%.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.153-157
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• 2009

A Highly efficient Mercury-free Flat Fluorescent Lamp (MFFL) with dielectric barrier Xe gas discharge was developed for an alternative of conventional line-type Cold Cathode Fluorescent Lamps (CCFLs) which shows a wide voltage margin and a stable discharge operation for diffuse glow discharge with an application of a auxiliary electrode. Electro-optic characteristics of the MFFL were examined through the changes in ambient temperature, total pressure and Xe partial pressure. the single cell is expanded into a multi-structured configuration to realize a large sized lamp by a simple repetition of the single cells, and a new driving scheme is proposed for an adaptive brightness control using dual auxiliary electrodes and bi-polar drive scheme. In addition, interesting application of this ultra high luminance flat lamp by the optimization of the gas condition and the pattern of the rear phosphor layer is suggested as a good alternative of daylight lamp source

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.56-64
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• 2002

In this work, a smart skin of multi-layer structure is designed and manufactured. Through the compression test, the characteristic of smart skin behavior was examined. We have predicted stress of each layer and the first failed layer of the smart skin structure by using MSC/NASTRAN. The finite element model was verified by comparing measured data from the compression test and result from the geometrically linear/non-linear analysis. The finite element model was used for obtaining design data from the parametric study. It was confirmed that shear moduli of honeycomb core affect the buckling load of smart skin where shear deformation was considerable.

• Korean Journal of Optics and Photonics
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• v.13 no.3
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• pp.209-214
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• 2002

The effect of surface roughness on mirror scattering has been studied. Five kinds of substrates with different surface roughness were fabricated. On those substrates, a dielectric multi-layer coating with high reflectivity was deposited by ion beam sputtering and electron beam evaporation. A total integrated scattering measurement set-up was built for the evaluation of deposited samples. Most of the ion beam sputtered mirrors showed lower scattering than the electron beam evaporated one, which deposited on substrates similar in surface roughness. Over ~2 $\AA$ in surface roughness, scattering strongly depend on the micro-structure of the super-polished surface. The lowest scattering we have achieved is 2.06 ppm by ion beam sputtering from the substrate with surface roughness of 0.23 $\AA$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.707-710
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• 2004

Chemical mechanical polishing (CMP) process has been widely used to planarize dielectric layers, which can be applied to the integrated circuits for sub-micron technology. Despite the increased use of CMP process, it is difficult to accomplish the global planarization of in the defect-free inter-level dielectrics (ILD). In this paper, we have investigated slurry properties and CMP performance of silicon dioxide (oxide) as a function of different temperature of slurry. Thermal effects on the silica slurry properties such as pH, particle size, conductivity and zeta potential were studied. Moreover, the relationship between the removal rate (RR) with WIWNU and slurry properties caused by changes of temperature were investigated. Therefore, the understanding of these temperature effects provides a foundation to optimize an oxide CMP Process for ULSI multi-level interconnection technology.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.11 s.102
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• pp.1067-1074
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• 2005

Studied antenna's basic structure was circular micro-strip patch antenna. Bandwidth was broaden and back-radiation pattern was decreased because studied antenna had PBG on a ground for improvement in its defect which is skin-effects. And character of antenna according to different shape of PBG was observed. Finally, air-gap whose dielectric constant is lower than substrates was added between substrates sc respond frequency was higher despite small size antenna.