• Title/Summary/Keyword: Temperature coefficient of resonant frequency

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Temperature Stability of Length-Extensional Vibration Modes in PZT Ceramics (PZT세라믹스에 있어서 길이진동모드의 온도안정성)

  • 이개명;현덕수
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.9
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    • pp.726-730
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    • 2001
  • Temperature stabilities of dielectric constraints and resonant frequencies of the substrates are very important in piezoelectric ceramics oscillators and filters. In this study, it was investigated temperature stability of the length-extensional vibration mode of Pb(Zr$\_$y/Ti$\_$1-y/)O$_3$+x[wt%]Cr$_2$O$_3$ ceramics. The mode can be utilized in fabricating ultra-small 455 kHz IF devices. Addition of Cr$_2$O$_3$ in morphotrophic phase PZT decreased the variations of dielectric constant, electro-mechanical coupling factor k$\_$31/ and resonant frequency by thermal shock. As additive weight of Cr$_2$O$_3$increased, the temperature coefficient of resonant frequency changed from positive number to negative one. And the composition tith temperature coefficient of resonant frequency was shifted to the one with increased Cr$_2$O$_3$ additive weigh by thermal aging.

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A Study on the Elastic Wave Delay Line (II) (탄성파지연선에 관한 연구(II))

  • 김종상
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.13 no.2
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    • pp.1-4
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    • 1976
  • In this paper, temperature dependence of the resonant frequency of thickness shear mode in X cut plate of $LiN_bO_3$ is theoretically analyzed. An a result of this analysis, theoretical value -78.43${\times}10^{-5}/^{\circ}C$ of the temperature coefficient of resonant frequency is obtained.

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Microwave Dielectric Properties of $(Pb_{1-x}Ca_x)ZrO_3$ and $(Pb_{0.63},Ca_{0.37-x}M_x)ZrO_3$ (M = Mg, Sr) Ceramics ($(Pb_{1-x}Ca_x)ZrO_3$$(Pb_{0.63},Ca_{0.37-x}M_x)ZrO_3$ 세라믹스의 고주파 유전 특성)

  • 윤중락;이헌용
    • Electrical & Electronic Materials
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    • v.10 no.6
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    • pp.533-540
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    • 1997
  • The microwave dielectric properties of ((P $b_{1-x}$ C $a_{x}$)Zr $O_3$ and (P $b_{0.63}$,C $a_{0.37-x}$ $M_{x}$)Zr $O_3$(M=Mg,Sr) ceramics were investigated. In (P $b_{1-x}$ C $a_{x}$)Zr $O_3$ (X=0.33~0.40) ceramics, high quality factor and small temperature coefficient of resonant frequency were obtain in (P $b_{0.63}$C $a_{0.37}$)Zr $O_3$with perovskite structure. In the case of (P $b_{0.63}$C $a_{0.37-x}$M $g_{x}$)Zr $O_3$ dielectric constant temperature coefficient of resonant frequency increased and quality factor decreased due to increase of polarization of A-O bonding. When replacing Ca ion with Sr ion with large ion radius, polarization decreased with increased of bonding length and thus dielectric constant and temperature coefficient of resonant frequency decreased.decreased.creased.

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A Study on the Microwave Dielectric Properties of 0.182BaO-0.818TiOS12T Ceramics (0.182BaO-0.818TiO2 세라믹스의 마이크로파 유전특성에 관한 연구)

  • 박인길;이영희;윤석진;정형진
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.43 no.3
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    • pp.442-446
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    • 1994
  • In this study, microwave dielectric properties of 0.182BaO-0.818TiOS12T ceramics were investigated with sintering temperature and annealing time, and the application for the microwave dielectric resonator was studied. In the specimen simtered at 1400[$^{\circ}C$], dielectric constant, unloaded Q and temperature coefficient of resonant frequency had good values of 35.36, 5692, -4.43[ppm/$^{\circ}C$], respectively. The specimen which temperature coefficient of resonant frequency($\tau$f) was vared positive to negative value was selected, thereafter microwave dielctric properties was investigated with annealing time(0~4[hr]) in the fixed annealing temperature of 1350[$^{\circ}C$]. Increasing the annealing time, dielectric constant and unloaded Q were increased and temperature coefficient of resonant frequency was decreased.

Dielectric, Piezoelectric Properties and Temperature Stability of Resonant Frequency in PSN-PMN-PZT Ceramics (PSN-PMN-PZT 세라믹스의 유전 및 압전 특성과 공진 주파수의 온도안정성)

  • 윤광희;류주현;민석규;이명수;서성재
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.391-395
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    • 2000
  • In this study, the temperature coefficient of resonant frequency(TC $F_{r}$), dielectric and piezoelectric properties of Pb[(S $b_{1}$2/N $b_{1}$2/)$_{0.0035}$-(M $n_{1}$3/N $b_{2}$3/)$_{0.0065}$-(Z $r_{x}$ $Ti_{1-x}$ )$_{0.90}$] $O_3$ceramics is investigated with Zr/Ti ratio. The dielectric constant and electromechanical coupling factor( $k_{p}$) showed the highest values of 1257, 0.562 respectively when the Zr/Ti ratio is 49.5/50.5. The mechanical quality factor( $Q_{m}$) is the lowest value of 713 when the Zr/Ti ratio is 49.5/50.5, and increased with the decrease of the Zr/Ti ratio. The temperature coefficient of resonant frequency(TC $F_{r}$) change abruptly at the morphotropic phase boundary(MPB), which is between the rhombohedral phase with highly negative TC $F_{r}$ of -106ppm/$^{\circ}C$ and the tetragonal phase with highly positive TC $F_{r}$ of +64pp $m^{\circ}C$ as Zr/Ti ratio changes from 50/50 to 49.5/50.5.50.5..5.50.5.5.

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Electrical Properties and Temperature Stability of resonant Frequency with Zr/Ti ratio in PSN-PMN-PZT Ceramics (PSN-PMN-PZT 세라믹스의 Zr/Ti 비에 따른 전기적 특성과 공진주파수의 온도안정성)

  • 류주현;윤광희;민석규;이명수;서성재
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.8
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    • pp.675-680
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    • 2000
  • In this study the temperature coefficient of resonant frequency(TC $F_{r}$) dielectric and piezoelectric properties of Pb[(S $b_{1}$2//N $b_{1}$2/)$_{0.065}$)-(Z $r_{x}$, $Ti_{1-x}$ )$_{0.90}$] $O_3$ceramics were investigated with Zr/Ti ratio. The compositions near the morphotropic phase boundary (MPB) appeared when Zr/Ti ratio was 49.5/50.5 The dielectric constant and electromechanical coupling factor( $k_{p}$) also showed the highest values of 1,257, 0.653 respectively when the Zr/Ti ratio was 49.5/50.5 Moreover the mechanical quality factor( $Q_{m}$) showed th lowest value of 713 when the Zr/Ti ratio. The temperature coefficient of resonant frequency(TC $F_{r}$) abruptly change at the morphotropic phase boundary(MPB) which existed between the rhombohedral phase with highly negative TC $F_{r}$ of -106ppm/$^{\circ}C$ and the tetragonal phase with highly positive TC $F_{r}$ of +64pp $m^{\circ}C$ as Zr/Ti ratio varied from 50/50 to 49.5/50.5.50.5..50.5.

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Microwave dielectric properties of the BSST ceramics with BaO compositional ratio (BSST계 세라믹스의 BaO 조성비에 따른 마이크로파 유전특성)

  • 박인길;정장호;이성갑;이영희
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.45 no.1
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    • pp.81-85
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    • 1996
  • Microwave dielectric properties of 0.15(B $a_{x}$S $r_{0.05}$)O-0.15(S $m_{2}$(1-y)N $d_{2y}$) $O_{3}$-0.7Ti $o_{2}$(x=o.9~0.1[mol.], y=6[m/o]) ceramics were investigated with BaO compositional ratio. Sintered density and resistivity of specimens were independent on the BaO compositional ratio. In the specimen with x=0.975[mol.], dielectric constant, quality factor and temperature coefficient of resonant frequency had good values of 76.52, 3001(at 3[GHz]) and +0.71[ppm/.ceg. C], respectively. By comparing with the stoichiometric compositions of 78.14, 2938(at 3[GHz])+14.19[ppm/.ceg. C], dielectric constant and quality factor showed similar properties, but the temperature coefficient of resonant frequency was highly improved. (author). refs., figs., tabs.s.s.

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Microwave Dielectric Properties of the (1-x)Mg$TiO_3$-xSr$TiO_3$(x=0.02~0.08)Ceramics with Sintering Temperature (소결온도에 따른 (1-x)Mg$TiO_3$-xSr$TiO_3$(x=0.02~0.08)세라믹스의 마이크로파 유전특성)

  • Choi, Eui-Sun;Lee, Sung-Gap;Bae, Seon-Gi;Lee, Young-Hie
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.12
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    • pp.1011-1016
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    • 2000
  • The (1-x)MgTi $O_3$-xSrTi $O_3$(x=0.02~0.08) ceramics were fabricated by the conventional mixed oxide method. The sintering temperature and time were 125$0^{\circ}C$~1375$^{\circ}C$ and 2hours. The structure and microwave dielectric properties were investigated with sintering temperature and composition ratio. From the X-ray diffraction patterns, the cubic SrTi $O_3$and hexagonal MgTi $O_3$structures were coexisted in the (1-x)MgTi $O_3$-xSrTi $O_3$(x=0.02~0.08) ceramics. The dielectric constant($\varepsilon$$_{r}$) was increased and the temperature coefficient of resonant frequency($\tau$$_{f}$)was decreased with addition of SrTi $O_3$. The temperature coefficient of resonant frequency($\tau$$_{f}$) was gradually varied from negative value to positive value with increasing SrTi $O_3$. In the case of 0.96MgTi $O_3$-0.04SrTi $O_3$ceramics sintered at 130$0^{\circ}C$, the dielectric constant, quality factor and temperature coefficient of resonant frequency were 20.5, 5918(at 7.33GHz) and +10ppm/$^{\circ}C$, respectively.y.y.y.

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Microwave dielectric properties of the 0.15(B $a_0.95$S $r_ 0.05$)O-0.15S $m_2$ $O_3$-0.7TiO $_2$ ceramics (0.15(B $a_0.95$S $r_ 0.05$)O-0.15S $m_2$ $O_3$-0.7TiO $_2$ 세라믹스의 마이크로파 유전특성)

  • 박인길;정장호;배선기;이영희
    • Electrical & Electronic Materials
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    • v.8 no.2
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    • pp.224-228
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    • 1995
  • 0.15(B $a_{0.95}$ S $r_{0.05}$)O-0.15S $m_{2}$ $O_{3}$-0.7Ti $O_{2}$ ceramics were fabricated by the mixed-oxide method. Microwave dielectric properties were investigated with sintering conditions. Increasing the sintering temperature from 1300 to 1375[.deg. C], the sintered density was increased from 5.44 to 5.63[g/c $m^{3$]. Increasing the sintering temperature, dielectric constant and quality factor were increased and temperature coefficient of resonant frequency was independent of sintering temperature. In the specimen sintered at 1375[.deg. C], dielectric constant, quality factor and temperature coefficient of resonant frequency were 80.79, 2784(at 3[GHz]), +11.07[ppm/.deg. C], respectively..

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Microwave Dielectric Properties of the MgTiO$_3$-SrTiO$_3$Ceramics (MgTiO$_3$-SrTiO$_3$세라믹스의 마이크로파 유전특성)

  • 최의선;이문기;정장호;김강;이영희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.843-846
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    • 2000
  • The (1-x)MgTiO$_3$-xSrTiO$_3$(x=0.02∼0.08) ceramics were fabricated by conventional mixed oxide method. The sintering temperature and time were 1250$^{\circ}C$∼1400$^{\circ}C$, 2hr., respectively. The structural and microwave dielectric properties were investigated by varying sintering temperature and composition ratio. In the (1-x)MgTiO$_3$-xSrTiO$_3$(x=0.02) ceramics, the cubic SrTiO$_3$and hexagonal MgTiO$_3$phases were coexisted. The dielectric constant was increased and the temperature coefficient of resonant frequency( $\tau_f$) was decreased with addition of SrTiO$_3$. The temperature coefficient of resonant frequency($\tau_f$) was gradually varied from negative value to positive value with increasing the SrTiO$_3$.

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