• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.9
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• pp.413-416
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• 2002

It was reported that low temperature plasma developed by our group was apparently homogeneous and stable at atmospheric pressure, and was generated if the alumina was used as a dielectric insulating material and Ar gas as a plasma gas. This is a structure in which the dielectric materials are covered and arranged in parallel in the one side of electrode. In this experiment, we discovered that dielectric material was important to generate normal electric discharge. To examine the effect of dielectric material on the electric discharge characteristic, the voltage and current of the plasma was measured and the electrical effect of dielectric material was examined. Also, it was applied to an etching of tin oxide films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.177-180
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• 1999

In this paper, we studied Surface Discharge Type Flat Fluorescent Lamp(FFL) with High Luminance for LCD Backlighting. This lamp is Surface Discharge Type structure with a pair of Sodalime glass, insulator layer, phosphor layer, and Xe gas gap. There are two influences of Electric field on different dielectric thickness. The Electric field difference at the dielectric layer itself enhances minimum value of firing voltage and luminance uniformity. So, we measured the Electric filed at 0.5mm, 1mm gap length and discharge voltage for difference dielectric layer thickness. In experiment result, the thicker dielectric layer has higher firing voltage and lower current.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.19.1-19.1
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• 2011

Effects of particle size, crystal structures and multilayer structures of $ATiO_3$, $ATa_2O_6$, $ANb_2O_6$, $AWO_4$, and $AMoO_4$ (A=Ni, Mg, Zn, Co) ceramic fillers on the dielectric properties of polystyrene (PS), polypropylene (PP) and polytetrafluoroethylene (PTFE) polymer matrices were investigated at microwave frequencies. The microwave dielectric properties of $ATiO_3$ (ilmenite), $ATa_2O_6$ (tri-rutile), $ANb_2O_6$ (columbite), AWO4 (wolframite), and AMoO4 (wolframite) ceramics were largely dependent on the structural characteristics of oxygen octahedra. The dielectric constant (K) of the composites was increased with the ceramic content. However, the dielectric loss (tan ${\delta}$) of the composites was affected by the type of ceramics and the crystallinity of polymers. For the composites with same amount of ceramics, the K was decreased and the tan ${\delta}$ was increased with the particle size of ceramics. Also, the dielectric properties of the composites were dependent on the multilayer structures with different arrangements. Several theoretical models have been employed to predict the effective dielectric properties of the composites. The frequency dependence of dielectric properties and the temperature coefficient of resonant frequency (TCF) of the composites were also discussed.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.1
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• pp.39-44
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• 1999

The dielectric layers in AC plasma display panel(PDP) are essential to the discharge cell structure, because they protect metal electrodes from sputtering by positive ion bombarding in discharge plasma and form a sheath of wall charges which are essential to memory function of AC PDP. This layer should have high dielectric breakdown voltage, and also be transparent because the luminance of PDP is strongly correlated this layer. In this paper, we discussed the dielectric breakdown voltage and transparency of the dielectric layer under various conditions. As a result, on the $15\mum$ thickness, the minimum dielectric breakdown voltage was 435V and the transmission coefficient was about 80% after $570^{\circ}C$ firing process. It can be proposed that the resonable dielectric thickness in AC PDP is $15\mum$ because it has about 75V margin on the maximum applied voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05b
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• pp.29-32
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• 2005

Poly (methyl methacrylate) (PMMA) is one of the promising representive of polymer gate dielectric for its high resistivity and sutible dielectric constant. PMMA (Mw=96700) films were prepared on p-Si by spin coating method. PMMA were coated compactively and flatly as observeed by AFM. MIS(Al/PMMA/p-Si) structure was made and capacitance-voltage (C-V) and current-voltage (I-V) measurements were done with PMMA films for different thermal treatment temperature. PMMA films were showed proper dielectric constant and breakdown voltage. Above the glass transition temperature PMMA films degraded. C-V measured at various frequencies, dielectric constant increased a little. The absence of hysteresis in the C-V characteristics, which eliminate the possibility of mobile charges in the PMMA films. The observed thermal stability, smooth surfaces, dielectric constant, I-V behavior implies PMMA formed by spin coating can be used as an efficient gate dielectric layer in OTFTs.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.323-333
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• 2007

In this paper, a new MDAS-DR antenna structure designed to efficiently shape a flat-topped radiation pattern is proposed. The antenna structure is composed of a stacked micro-strip patch exciter and a multi-layered disk array structure(MDAS) surrounded by a dielectric ring. The MDAS, which was supplied by a stacked microstrip patch exciter with radiating power, can form a flat-topped radiation pattern in a far field by a mutual interaction with the surrounding dielectric ring. Therefore, the design parameters of the dielectric ring and the MDAS structure are important design parameters for shaping a flat-topped radiation pattern. The proposed antenna used twelve multi-layered disk array elements and a Teflon material with a dielectric constant of 2.05. An antenna operated at 10 GHz$(9.6\sim10.4\;GHz)$ was designed in order to verify the effectiveness of the proposed antenna structure. The commercial simulator of CST Microwave $Studio^{TM}$, which was adapted to a 3-D antenna structure analysis, was used for the simulation. The antenna breadboard was also fabricated and its electrical performance was measured in an anechoic antenna chamber. The measured results of the antenna breadboard with a flat-topped radiation pattern were found to be in good agreement with the simulated one. The MDAS-DR antenna gain measured at 10 GHz was 11.18 dBi, and the MDAS-DR antenna was capable of shaping a good flat-topped radiation pattern with a beam-width of about $40^{\circ}$, at least within a fractional bandwidth of 8.0 %.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.11a
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• pp.119-123
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• 2001

In this paper, a new structure and fabrication method for the wafer level package(WLP) is presented. A packaged VLSI chip is encapsulated by a parylene(which is a low k material) layer as a dielectric layer and is molded by SUB photo-epoxy with dielectric constant of 3.0 at 100 MHz. The electrical parameters (R, L, C) of package traces are extracted by using the Maxwell 3-D simulator. Based on HSPICE simulation results, the proposed wafer level package can operate for frequencies up to 20GHz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.49-52
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• 1998

In this paper, to implement the electrical equivalent modeling of powder electroluminescent device, capacitate equation of device was chosen. The conventional structure device which have dielectric and phosphor layer between electrodes, and the single emission structure device which means that dielectric and phosphor were mixed between electrodes, were investigated. As a result, it was possible to make the equation that is transferred capacitance to phosphor layer, and using measured brightness efficiency and conductivity of devices was calculated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.894-896
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• 2001

The Polypropylene films which are made by refinement of its pellet and formed as crystals are exposed to Radiation. As the results, degradation effects were observed in non-crystalline regions. It is thus considered that the effects occur by destroying of lattice binding force by Radiation. The distribution of degradation was increased with irradiation quantities of Radiation and dielectric constant of Polypropylene sheets irradiated Radiation was rapidly increased from above 10 MHz.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.5
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• pp.217-222
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• 2007

Microwave dielectric properties of $(1-x)CaWO_4-xYNbO_4$ ceramics have been investigated as a function of $YNbO_4$ content($0.05{\leq}x{\leq}0.4$). A single phase with tetragonal scheelite structure was obtained up to x=0.10 and then the secondary phase with fergusonite structure was increased. With the increase of $YNbO_4$ content, apparent densities of the specimens were decreased. This results were due to the lower theoretical density of $YNbO_4(5.581g/cm^3)$ than that of $CaWO_4(6.117g/cm^3)$. Dielectric constant(K) and quality factor(Qf) were decreased with $YNbO_4$ content which could be attribute to the decrease of density and the increase of secondary phase. Temperature coefficient of resonant frequency (TCF) of the specimens with the $YNbO_4$ content was depended on dielectric mixing rule.