• 한국재료학회지
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• 제19권10호
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• pp.550-554
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• 2009

Unreported dielectrics based on the binary system of MgO-SiO$_2$ were investigated as potential candidates for microwave dielectric applications, particularly those demanding a high fired density and high quality factors. Extensive dielectric compositions having different molar ratios of MgO to SiO$_2$, such as 2:1, 3:1, 4:1, and 5:1, were prepared by conventional solid state reactions between MgO and SiO$_2$. 1 mol% of V$_2$O$_5$ was added to aid sintering for improved densification. The dielectric compositions were found to consist of two distinguishable phases of Mg$_2$SiO$_4$ and MgO beyond the 2:1 compositional ratio, which determined the final physical and dielectric properties of the corresponding composite samples. The increase of the ratio of MgO to SiO$_2$ tended to improve fired density and quality factor (Q) without increasing grain size. As a promising composition, the 5MgO.SiO$_2$ sample sintered at 1400 $^{\circ}C$ exhibited a low dielectric constant of 7.9 and a high Q $\times$ f (frequency) value of $\sim$99,600 at 13.7 GHz.

• 한국재료학회지
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• 제29권3호
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• pp.175-182
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• 2019

This study examines paraelectric $Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7$ (BZN), which has no hysteresis and high dielectric strength, for energy density capacitor applications. To increase the breakdown dielectric strength of the BZN film further, poly(vinylidene fluoride) BZN-PVDF composite film is fabricated by aerosol deposition. The volume ratio of each composition is calculated using dielectric constant of each composition, and we find that it was 12:88 vol% (BZN:PVDF). To modulate the structure and dielectric properties of the ferroelectric polymer PVDF, the composite film is heat-treated at $200^{\circ}C$ for 5 and 30 minutes following quenching. The amount of ${\alpha}-phase$ in the PVDF increases with an increasing annealing time, which in turn decreases the dielectric constant and dielectric loss. The breakdown dielectric strength of the BZN film increases by mixing PVDF. However, the breakdown field decreases with an increasing annealing time. The BZN-PVDF composite film has the energy density of $4.9J/cm^3$, which is larger than that of the pure BZN film of $3.6J/cm^3$.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1248-1251
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• 2005

In PDP, a transparent dielectric is formed on a front glass substrate so as to cover bus electrodes (Ag). During the fabrication process, sometimes, a transparent dielectric reacts with bus (Ag) electrode in the range of $560-600^{\circ}C$, and the reaction gives the dielectric its yellow coloration, what is called "yellowing phenomena". In this paper, we investigated the reaction between bus electrode and transparent dielectric covered with different frit content in Ag paste.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1444-1446
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• 2009

The atmospheric pressure plasma polymerization of acrylate monomers was carried out to have dielectrics with easy preparation and high performance. The effects of discharge power, monomer concentration and deposition time on film properties were investigated using various characterization tools. With proper conditions, smooth dielectric layer of 100nm thickness was obtained. Dielectric property as organic dielectric layer has been studied for future applications in organic thin film transistors(OTFT).

• 한국재료학회:학술대회논문집
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• 한국재료학회 2008년도 춘계학술발표대회 및 제14회 신소재 심포지엄
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• pp.16.1-16.1
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• 2008

• Composites Research
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• 제14권1호
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• pp.30-38
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• 2001

복합재료는 우수한 비강성, 비강도 특성 때문에 기존의 항공우주산업뿐만 아니라 로봇 팔. 공작기계 등에 널리 사용되고 있다. 복합재료 경화중의 온라인 모니터링기법은 생산성 향상 및 품질의 신뢰성 향상을 위하여 매우 중요한 연구분야로 대두되고 있다. 본 논문에서는 휘스톤 브리지식 유전회로를 설계하고 제작하였다. 또한 고온 경화 복합재료에 적용할 수 있는 고온 유전센서를 개발하여 그 성능을 평가하였다. 유한요소해석을 이용하여 유전 센서에 작용하는 열 잔류응력을 계산하였으며, 고온분위기 하에서 유전센서의 유전특성을 평가하였다. 이상에서 개발된 유전회로와 고온 유전센서를 이용하여 BMI(Blsmaleimlde) 수지의 경화모니터링을 수행하였다.

• Journal of electromagnetic engineering and science
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• 제6권1호
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• pp.1-9
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• 2006

A sandwich structure of dielectric material and air gap inside a rectangular waveguide is proposed as a fast electrically tunable low-loss phase shifter. As the dielectric material is shifted up and down by piezoelectric actuator and, thereby, the thickness of air gap is changed, the effective dielectric constant of the sandwich structure is varied. Phase shifters based on the sandwich structure with different dielectric materials showed phase shift of $20{\sim}200^{\circ}/cm$ at X-band as the thickness of air gap varied up to $30{\mu}m$. The idea can be extended toward low-loss millimeter wave phase shifters since modem microwave ceramics have been developed to show very low dielectric loss$(tan\;{\delta}{\sim}10^{-4})$.

• 한국진공학회지
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• 제5권2호
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• pp.161-168
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• 1996

For the improvement of microelectronic thin film interconnection materials, dielectric passivation effects on the electromigration phenomena were studied. Using Al-1%Si, various shaped patterns were fabricated and dielectric passivation layers of several structures were deposited on the $SiO_2$ layer. Lifetime of straight pattern showed 2~5 times longer than the other patterns that had various line width and area. It is believed that the flux divergence due to the structural inhomogeneity and so the current crowding effects shorten the lifetime of thin film interconnections. The lifetime of thin film interconnections seems to depend on both the passivation materials and the passivation thickness. PSG/$SiO_2$ dielectric passivation layers showed longer lifetime than $Si_3N_4$ dielectric passivation layers. This results from the PSG on $SiO_2$ layer reduces stress and from the improvement of resistance to the moisture and to the mobile ion such as sodium. This is also believed that the lifetime of thin film interconnections seems to depend on the passivation thickness in case of the same deposition materials.

• E2M - 전기 전자와 첨단 소재
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• 제10권7호
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• pp.651-658
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• 1997

In this paper, effect of interpenetrating polymer network(IPN) introduction on the dielectric properties, heat proof properties, internal structure and defects of the Epoxy/SiO$_2$composite materials, were investigated. we reported a relation between network structures and electrical properties, especially dielectric characteristics with variation of network structures for epoxy composite materials. According to experimental results, the specimens which have single network structures have lower dielectric constant than interpenetrating polymer network(IPN) specimens, but have relatively larger dependency to variation of temperature and frequency. It was confirmed that change of structures is attained by introducing of IPN to insulating materials. Therefore it is counted that introduction of multiple structure including IPN is necessary to improve heat proof and electrical properties.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.978-983
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• 2014

The polymer nano composite possess good priority recently for engineering applications. Especially the electrical insulating materials attract the high performance of nano composites. In this work the ballmill synthesiation process of nano sized Alumina ($Al_2O_3$), the preparation of new nano composite material with an content of enamel and synthesized Alumina as 1wt%, 3wt% and 5wt%. Experimental investigation has been carried out for the prepared nano composites materials with respect to dielectric parameter measurements such as dielectric loss (tan ${\delta}$), dielectric constant (${\varepsilon}$), dielectric strength under various temperature. The partial discharge level also measured for all the samples and the PD inception voltage is also observed and compared. Weight loss of the material has been analyzed through TGA. It has been experimentally proved that 3wt% of Alumina nano filler added enamel has significant improvement in the dielectric and thermal properties.