• 제목/요약/키워드: Microwave dielectrics

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$ZnWO_4$ 세라믹의 마이크로파 유전특성 (Microwave Dielectric Properties of $ZnWO_4$ Ceramics)

  • 윤상옥;윤종훈;김대민;심상흥;강기성
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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    • pp.642-645
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    • 2002

  • Microwave dielectric properties of $ZnWO_4$ ceramic were investigated with calcination and sintering temperatures. The dielectric properties required for such application are high dielectric constant$(\varepsilon_r)$, high $Q{\times}f_o$ value and low temperature coefficient of resonant frequency$(\tau_f)$. These requirement correspond to necessities for size reduction, excellent frequency selectivity, good temperature stability of devices. $ZnWO_4$ ceramics could be sintered at low $1075^{\circ}C$, which was comparatively low temperature for microwave dielectrics. As a result, $ZnWO_4$ showed the dielectric constant of 13, quality factor($Q{\times}f_o$ value) of 22000 and 'temperature coefficient of resonant frequency$(\tau_f)$ of $-65{\pm}5ppm/^{\circ}C$.

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마이크로파 유전체의 미세구조와 품질계수의 상관관계에 대한 컴퓨터 시뮬레이션 (Electromagnetic Simulation of the Quality Factor and Microstructure of Microwave Dielectrics)

  • 박재환;박재관
    • 한국재료학회지
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    • 제11권2호
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    • pp.146-150
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    • 2001

  • 마이크로파 유전체의 품질계수 측정에 사용되는 cavity resonator 방법에 대하여 실제 측정 결과와 전자기 시뮬레이션엔 의한 결과를 비교하였다. 시뮬레이션 기법을 이용하여 마이크로파 유전체의 산란계수 $S_{12}$ 를 실제로 측정한 간과 시뮬레이션에 의해 구해진 값을 비교하였으며 마이크로파 유전체 내부에 기공이 있는 경우와 유전율이 다른 이차상이 존재할 때 마이크로파 품질계수가 어떻게 변화하는지를 검토하였다. 시뮬레이션을 통하여 기본 공진 모드인 $TE_{01\delta}$모드를 쉽게 찾을 수 있었으며 기공 및 이차상에 의한 품질계수의 저하를 정성적으로 확인할 수 있었다

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붕규산염 유리 첨가에 따른 $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$의 저온 소결 및 유전 특성 (Low Temperature Sintering and Dielectric Properties of $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$ with (ZBS, BZBS) glasses)

  • 김관수;박종국;윤상옥;김신;김윤한;강석용
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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    • pp.342-342
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    • 2008

  • The low temperature sintering and microwave dielectric properties of ceramic/glass composites which were composed of ceramics in the $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$ and zinc borosilicate glass/bismuth-zinc borosilicate glass were investigated with a view to applying the microwave dielectrics to low temperature co-fired ceramics. The $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$ addition of 5 wt% ZBS and BZBS glass ensured a successful sintering below $900^{\circ}C$. In addition, pyrochlore phase was observed in the all composition. $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$ with 5 wt% BZBS glasss demonstrated 70 as the dielectric constant ($\varepsilon_r$), 2,500 GHz as the Q$\times$f value, and -40 ppm/$^{\circ}C$ as TCF.

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$Ba_5Nb_4O_{15}$ Ceramics with Temperature-Stable High Dielectric Constant and Low Microwave Loss

  • Woo Hwan Jung;Jeong Ho Sohn;Yoshiyuki Inaguma;Mitsuru Itoh
    • The Korean Journal of Ceramics
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    • 제2권2호
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    • pp.111-113
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    • 1996

  • Dielectric properties at microwave frequency region of the five-layered compound $Ba_5Nb_4O_{15}$ prepared by the conventional solid state reaction method were investigated. $Ba_5Nb_4O_{15}$ has excellent microwave dielectric characteristics; ${\varepsilon}_r$=38, Q=7500 at 10 GHz, and ${\tau}_l$=+50 ppm/K. Since this compound has a high dielectric constant, high Q and sufficiently stable characteristics, it is useful for the applications at microwave frequencies.

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