• Title, Summary, Keyword: dielectric

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Dielectric Characteristics on Filler Content and Sintering Temperature in Pb-Free White Dielectric Layer (Pb-Free 백색유전체에서 필러함량과 소성온도에 따른 유전체 특성)

  • An, Yong-Tae;Choi, Byung-Hyun;Ji, Mi-Jung;Lee, Jung-Min;Kim, Hyun-Sun;Jung, Kyung-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.8
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    • pp.755-759
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    • 2008
  • For the development of a new white dielectric layer in plasma display panel, different $TiO_2$ types as a filler was add to the $Bi_2O_3$-BaO-ZnO glass matrix. The reflectance and dielectric constant of dielectric have been investigated as a function of the mixing content (rutile and anatase), and sintering temperature. The reflectance of dielectric sintered at the 520$^{\circ}C$ appeared most highly and suitable in terms of the adhesion and reflectance of the soda-lime glasses. Also, the thermal expansion coefficient of dielectric was found to be $85.6\times10^{-7}/K$, which was similar to that of the soda-lime glasses. Especially, the dielectric constants were not increased with increasing of $TiO_2$ filler contents.

Temperature, Electric Field, Pressure Dependency and Dielectric properties on the interface between XLPE and EPDM (XLPE와 EPDM의 계면에 따른 유전특성과 온도, 전계, 압력의존성)

  • 김동식;박대희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.109-111
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    • 1997
  • In this paper, we have evaluated temperature, electric field, Pressure dependency and dielectric properties of EPDM XLPE and EPDM/XLPE\`s interface. Temperature dependency of EPDM had great influence with dielectric properties, but pressure and applied voltage of EPDM had no effect on dielectric properties. Dielectric properties of XLPE were influenced by not only temperature but also pressure and applied voltage. We knowed that dielectric properties of EPDM/XLPE were trended toward tendency of those of EPDM

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Design of A Dielectric-Slab Polarizer in The Circular Waveguide (유전체판을 이용한 원형 도파관 편파기의 설계)

  • 김영민;안병철
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.87-90
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    • 2000
  • In this paper. we present a method for a systematic design of a dielectric slab polarizer in the circular waveguide. This structure is realized using a tapered dielectric slab inside a circular waveguide. Commercial software is used to obtain the equivalent dielectric constant of the circular waveguide partially filled with a dielectric slab. The length of the tapered region is determined so that the reflection from the dielectric slab is sufficiently low. A polarizer operating at 10 GHz band is designed, fabricated and tested.

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Analysis of Shielding Characteristics on the Cylindrical Lossy Multilayered Dielectric (손실이 있는 원통형 다층 유전체의 차폐특성 해석)

  • Ryu, Hwang;Lee, Sang-Seul
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.11
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    • pp.57-61
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    • 1992
  • In this paper, the shielding characteristics of a cylindrical multilayered dielectric are analyzed. In order to evaluate shielding effects, we consider the case that plane waves are incident upon an infinitely long cylindrical multilayered dielectric which surrounds a conductor core. For perfect and lossy dielectric distributions, total induced currents at the conductor surface are computed. It was found from those results that electromagnetic characteristics of the multilayered dielectric are largely dependent on dielectric distribution.

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Dielectric Properties of Agricultural Properties and Their Use in Moisture Sensing and Other Applications

  • Nelson, Stuart O.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • pp.293-304
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    • 1996
  • Historical interest in dielectric properties of agricultural products and definitions of dielectric terms and basic principles governing their influence on elelctromagnetic energy are presented briefly . The nature of dielectric properties variation with frequency, temperature , and product density is discussed, Graphical data on the dielectric properties of products are presented that illustrate the dependence of these properties on moisture content, frequency, temperature, and density. Applications microwave dielectric properties of agricultural products are cited that include radio-frequency (RF) and microwave heating for seed treatment, improvement of nutritional and keeping qualities of some products, and controlling insects in grain. Uses of dielectric properties for product quality measurement and the rapid determination of moisture content are described. Principle of moisture determination in bulk grain by RF and microwave measurements are briefly presented.

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The Influence of $Ta_2O_{5}$ Addition on Dielectric Characteristics of Zirconium Titanate Ceramics (Zirconium Titanate 세라믹 유전체에서 $Ta_2O_{5}$ 첨가가 유전특성에 미치는 영향)

  • 이석진;이창화;이상석;최태구
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.129-132
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    • 1992
  • Rutile was among the first dielectric materials used. However, rutile exhibits a very high temperature coefficient of capacitance (about -750[ppm/$^{\circ}C$]) which resticts its practical application. Since this first use of titania, other materials have also been studied with the object of decreasing the temperature dependence whilst retaining favorable dielectric loss, Q, and relative permittivity. The temperature coefficient of temperature compensation capacitor is +100~750[ppm/$^{\circ}C$], dielectric constant 10~150. Low loss ceramics with dielectric constants in the 10~150 range also found application. Recently, their applications are extended in EMI filter and dielectric materials for microwave. There temperature coefficient of dielectric materials approaches 0[ppm/$^{\circ}C$]. The dielectric preperties of zirconia titanate ceramics prepared by addition of $Ta_2O_{5}$ were investigated.

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Improvement of Heating Pattern in RF Hyperthermia -Simultaneous Application of Dielectric Heating and Induction Heating-

  • Sakakibara, Norifumi;Ochiai, Makoto;Hayakawa, Yoshinori
    • Proceedings of the Korean Society of Medical Physics Conference
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    • pp.478-480
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    • 2002
  • Heating by RF wave is divided into dielectric heating and induction heating. Dielectric heating and induction heating from outside the body have the compensatory heating pattern. While surface fat layer is heated by dielectric heating, it is not heated by induction heating. While the peripheral part at the middle of the electrodes is not heated by dielectric heating, it is heated by induction heating. By the simultaneous application both modalities, heating pattern seems to be more uniform and improved. Computer simulation of Finite Element Method (FEM) using ANSYS was conducted to dielectric heating with the results of above-mentioned feature. Theoretical considerations by the uniform RF magnetic field in a cylinder and textbooks support the feature of the above-mentioned heating pattern of induction heating. Further computer simulation of FEM using ANSYS will be conducted to simultaneous application of dielectric heating and induction heating to verify and will be reported.

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Dielectric Characteristics of Composite dielectric Film for Pulsed Power Capacitors (커패시터용 복합유전체필름의 유전특성 분석)

  • Park, J.D.;Kwak, H.R.;Park, H.Y.;Jung, J.W.
    • Proceedings of the KIEE Conference
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    • pp.1661-1663
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    • 2001
  • This paper describes the dielectric characteristics of composite dielectric film for pulsed power capacitors. The relative electric permittivity(${\varepsilon}'$) and the dielectric dissipation factor(tan$\delta$) were measured for polypropylene (PP) membranes, kraft paper for capacitors(CP) and composite dielectric films(PP+CP), respectively, in a frequency range of $1{\sim}10^4$[Hz], and in temperatures ranging from -50[$^{\circ}C$] to 110[$^{\circ}C$]. As a result, the variation of the electric permittivity was observed similarly for PP and CP. Dielectric dispersion was observed in frequency domain in PP, CP and composite dielectric films.

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Characterization of Thin Film Transistor using $Ta_2O_5$ Gate Dielectric

  • Um, Myung-Yoon;Lee, Seok-Kiu;Kim, Hyeong-Joon
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.157-158
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    • 2000
  • In this study, to get the larger drain current of the device under the same operation condition as the conventional gate dielectric SiNx thin film transistor devices, we introduced new gate dielectric $Ta_2O_5$ thin film which has high dielectric constant $({\sim}25)$ and good electrical reliabilities. For the application for the TFT device, we fabricated the $Ta_2O_5$ gate dielectric TFT on the low-temperature-transformed polycrystalline silicon thin film using the self-aligned implantation processing technology for source/drain and gate doping. The $Ta_2O_5$ gate dielectric TFT showed better electrical performance than SiNx gate dielectric TFT because of the higher dielectric constant.

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유전체 재료를 활용한 이동통신 필터 기술

  • 김준철;방규석;이형규
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.3
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    • pp.25-34
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    • 2001
  • There are many kinds of dielectric materials in microwave dielectric filters for mobile telecomunication. But It is need to new dielectric materials for IMT200O, Bluetooth, wireless LAN to miniaturize the dielectric filters. These kinds of materials should have high dielectric constants, high Q, and low firing sintering temperature(<900˚C ). Multilayer monolithic dielectric filters are manufactured by BiNb04, dielectric ceramics cofired at 875˚C .

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