• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.290-291
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• 2007

In this study, in order to develop low temperature sintering ceramics for multilayer piezoelectric actuator, sensers, transducers, PMN-PNN-PZT ceramics were manufacrtured with the sintering temperature, and their piezoelectric and dielectric properties were investigated. At the composition ceramics sintered at $900^{\circ}C$, desity, dielectric constant$({\varepsilon}_r)$, electromechanical coupling factor(kp), piezoelectric constant$(d_{33})$ and mechanical quality factor(Qm) showed the optimal value of $7.86g/cm^3$, 1417, 0.634, 410pC/N and 1138, respectively.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1103-1105
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• 1993

Microwave characteristics of the system (1-X) ${Na}_{1/2}{Sm}_{1/2}TiO_3$[NST]-X ${Li}_{1/2}{Nd}_{1/2}TiO_3$[LNT] were investigated. The dielectric constant and unloaded Q were 86,1950 respectively for NST at 3GHz and 80,500 for LNT. 0.4 NST - 0.6 LNT system has the dielectric constant ${\varepsilon}r$=86.2, Q=930(3GHz), temperature coefficient of the resonant frequency ${\tau}f$ = 8 ppm/$^{\circ}C$ when sintered at $1450^{\circ}C$ for 2h.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.125-128
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• 1999

(Ba$_{0.6}$Sr$_{0.4}$)TiO$_3$(BST) thin films were fabricated with different deposition temperature by Pulsed Laser Deposition(PLD). This BST thin films showed a maximum dielectric constant value of $\varepsilon$$_{r}$=~684 and dielectric loss was ~0.01 when substrate temperature was 75$0^{\circ}C$. Charge storage density of BST thin film was 4.733 [$\mu$C/$\textrm{cm}^2$] and estimated charging time was 0.15 nsec. Leakage current density of BST thin film was below 10$^{-7}$ [A/$\textrm{cm}^2$] at 3V. 3V.V.

• The Korean Journal of Ceramics
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• v.1 no.1
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• pp.13-20
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• 1995

Effects of thermal annealing on the dielectric/piezoelectric properties of $Pb(Zn, Mg)_{1/3}Nb_{2/3}O_3-PbTiO_3$ ceramics (PZMNPT) with Zn/Mg=6/4) were examined across the rhombohedral/tetragonal morphotropic phase boundary (MPB). Both the relative dielectric permittivity ($\varepsilon$r)and the piezoelectric constant($d_33$)/electromechanical coupling constant ($k_p$)were increased by thermal annealing ($800^{\circ}$~$900^{\circ}C$) after sintering at $1150^{\circ}C$ for 1 hr. Based on the dielectric analysis using the series mixing model and the concept of a random distribution of the local Curie points, the observed improvements in the dielectric and piezoelectric properties of PZMN-PT were interpreted in terms of the elimination of PbO-rich amorphous intergranular layers(~1nm) induced by thermal annealing. A concrete evidence of the presence of amorphous grain-boundary layers in the unannealed (as-sintered) specimen was obtained by examining the structure of intergranular region using a TEM.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.177-177
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• 2008

The effect of several $SiO_2-B_2O_3-Al_2O_3$-R(R;Ca, Sr, Ba) borosilicate glass system on sintering behavior, dielectric properties and mechanical properties of glass/ceramic composites were investigated. The amount of '+2 valency' metal elements(Ca, Sr, Ba) were examined in LTCC composite of low k glass with cordierite filler. It was sintered for 60minutes in temperature range from 850C to 950. Properties of frit and glass/ceramic composites were analyzed by DTA, XRD, SEM, Network Analyzer, UTM and so on. Dielectric constant ($\varepsilon_r$) and $Q{\times}f_0$ (Q) of the composite with 50% glass contents demonstrated $\varepsilon_r$ = 5.4 $Q{\times}f_0$ = 1600 GHz. Sintering was complete and maximum bending strength of 160MPa was obtained.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.10
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• pp.1-6
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• 1998

The dielectric effects of plastic packages on GaAs($\varepsilon$$_{r}$=13) MMIC microstrip characteristics are analyzed using the spectral domain method (SDM). As being packaged by typical FR-4 composites ($\varepsilon$$_{r}$=14.2) for PCB substrates and plastic packages, the characteristic impedance is reduced by about 6 %, but the effective dielectric constant is increased by 13 % from those of bare microstrip, respectively. The parasitic effects of the packaging materials can greatly degrade the performance of the packaged MMIC. We also calculated the optimum microstrip width, which maintains the 50 $\Omega$ matching condition after plastic packaging. These calculated results can be used to optimize the plastic packages, and extend the application ranges for low cost MMIC production.n.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1044-1051
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• 2003

In this paper, a compact planar microwave duplexer on the high dielectric substrate is presented. As the Ba(Mg$\sub$1/3/Ta$\sub$2/3/)O$_3$(BMT) has good dielectric performances with a high dielectric constant of $\varepsilon$$\sub$r/=23, it is suitable to apply to a printed circuit board fur reducing its circuit size. The BMT substrate is fabricated by using a tape casting fabrication process, and circuit patterns are screen-printed on it by suing silver paste. The open-loop ring type duplexer is designed and implemented on the BMT substrate, and it achieves the smaller size by 80% than one on a commercial substrate($\varepsilon$$\sub$r/=6.15) without degenerating its performance. Therefore the proposed BMT substrate has provided the miniaturization of the duplexer, moreover it can make a contribution towards reducing the size of microwave passive circuits.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.981-984
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• 2001

The piezoelectric properties of 0.05pb(A $l_{0.5}$N $b_{0.5}$) $O_3$-0.95Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_3$+0.7wt%N $b_2$ $O_{5}$ +0.5wt%Mn $O_2$ceramics with the additives of BaC $O_3$were investigated. For the additions of BaC $O_3$, the dielectric constant ($\varepsilon$$^{T}$ $_{33}$ ), the piezoelectric constant ( $d_{33}$ ), the electromechanical coupling factor ( $k_{p}$ ), and . the mechanical quality factor ( $Q_{m}$ ) were increased, but dielectric loss (tan$\delta$) was decreased. The highest piezoelectric properties and dielectric properties were observed at the sintered temperature of 120$0^{\circ}C$ and 0.4 wt% of BaC $O_3$, and the properties of $d_{33}$ , $k_{p}$ , and $Q_{m}$ were 339(x10$^{-12}$ C/N), 59% and 1754, respectively.vely.y.y.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.117-120
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• 2004

The dielectric and piezoelectric properties of silver doped $Pb(Zr,Ti)O_3-Pb(Mn,W,Sb,Nb)O_3$ ceramics was examined. By varying the contents of silver(0.0, 0.4, 1.0 mol%), the effect of doped silver on PZT-PMWSN thin film was investigated at various sintering temperature(900, 1000, $1100^{\circ}C$). As increasing silver contents, the relative dielectric constant is increased and sinterbility is enhanced. At the specimen with 0.4 mol% Ag and sintered at $1100^{\circ}C$, electromechanical coupling factor(kp), mechanical quality factor(Qm), dielectric constant(${\varepsilon}r$) and dielectric loss were 0.502, 811, 991, 0.006, respectively. The results show that the PZT-PMWSN/Ag composites have enhanced piezoelectic and dielectric properties and processing condition is improved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.09a
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• pp.72-75
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• 2001

In this paper, the $Sr_{1-x}Ca_{x}TiO_{3}(0{\leq}x{\leq}0.2)$ 2)-based grain boundary layer ceramics were fabricated to measured dielectric properties and voltage-current properties. The sintering temperature and time were $1420\sim1520^{\circ}C$, 4hours, in $N_{2}$ gas, respectively. The structural and the dielectric properties were investigated by SEM, X-ray, HP4194A and K6517. The 2nd phase formed by thermal diffusion from the surface lead to a very high apparent dielectric constant, $\varepsilon_r$ > 50000. X-ray diffraction patterns exhibited cubic structure for all specimens. Increasing content of Ca, the peak intensity were decreased.ﱇﶖ⨀ਆᘍ܀㘱㔮㠹㬅K䍄乍