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유전체 공진기를 이용한 개인휴대 통신용 대역통과 필터의 설계 및 구현
권정열,이헌용,홍성용,윤중락 明知大學校 産業技術硏究所 1996 産業技術硏究所論文集 Vol.15 No.-
In this paper, the band pass filter for personal communication services was constructed and designed using λ/4 TEM mode dielectric resonators with a (Zr0.65,Sn0.35)ATi1.04O4.04 ceramic of dielectric constant εr=37.8, Qxfo=48.600 temperature coefficient of resonant frequency rf=7ppm/˚C, and Unloaded-Q (Qo) of λ/4 TEM mode dielectric resonator with inner hole size 0.9㎜ and external size 3㎜ using silver electrode is 354.5 at 1950MHz. For the band pass filter design and construction, the design theory and simulation results of band pass filter using J-inverter theory have been studied. The parameters which are evaluated by design theory are practically applied to the filter construction and the simulation results are in agreement with the measured results after fine tunnings.
Yoon, Jung Rag,Lee, Chang-Bae,Lee, Serk Won,Lee, Heun-Young The Korean Institute of Electrical and Electronic 2012 Transactions on Electrical and Electronic Material Vol.13 No.6
(1-X)$(Na_{0.5}K_{0.5})NbO_3-XK_{5.4}Cu_{1.3}Ta_{10}O_{29}$ (NKN-KCT) lead-free piezoelectric ceramics have been synthesized by the conventional solid state sintering method, and their sinterability and piezoelectric properties were investigated. Typically, this material is sintered between 1,025 and $1,100^{\circ}C$ for 2 hours to achieve the required densification. Crystalline structures and Microstructures were analyzed by X-ray diffraction and scanning electron microscope. The density, dielectric constant (${\varepsilon}_r$), piezoelectric constant $d_{33}$, electromechanical coupling factor $k_p$ and mechanical quality factor $Q_m$ value of the NKN ceramics depended upon the KCT content and the sintering temperature. In particular, the KCT addition to NKN greatly improved the mechanical quality factor $Q_m$ value. The ceramic with X = 1.0 mol% sintered at $1,050^{\circ}C$ exhibited optimum properties (${\varepsilon}_r$=246, $d_{33}$=95, $k_p$=0.38 and $Q_m$=1,826). These results indicate that the ceramic is a promising candidate material for applications in lead free piezoelectric transformer and filter materials.
Jung Rag Yoon,Chang-Bae Lee,이석원,이헌용 한국전기전자재료학회 2012 Transactions on Electrical and Electronic Material Vol.13 No.6
(1-X)(Na0.5K0.5)NbO3-XK5.4Cu1.3Ta10O29 (NKN-KCT) lead-free piezoelectric ceramics have been synthesized by the conventional solid state sintering method, and their sinterability and piezoelectric properties were investigated. Typically, this material is sintered between 1,025 and 1,100℃ for 2 hours to achieve the required densification. Crystalline structures and Microstructures were analyzed by X-ray diffraction and scanning electron microscope. The density, dielectric constant (εr), piezoelectric constant d33, electromechanical coupling factor kp and mechanical quality factor Qm value of the NKN ceramics depended upon the KCT content and the sintering temperature. In particular, the KCT addition to NKN greatly improved the mechanical quality factor Qm value. The ceramic with X =1.0 mol% sintered at 1,050℃ exhibited optimum properties (εr= 246, d33= 95, kp= 0.38 and Qm= 1,826). These results indicate that the ceramic is a promising candidate material for applications in lead free piezoelectric transformer and filter materials.
Electrical Characteristics of Multilayered Ceramic Capacitors Depending on BaTiO 3 Particle Size
Jung Rag Yoon,Min-Kee Kim 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.6
Multilayer ceramic capacitors were prepared with BaTiO 3 -based ceramics of diff erent grain sizes (150–500 nm), having appropriate dielectric properties and high-temperature stability. The grain size eff ect on the dielectric properties and insulation resistivity of fi ne-grained BaTiO 3 ceramics at room temperature and high temperatures under electric fi elds were investigated. The reduction in particle size has a strong eff ect on DC-bias characteristics and withstanding voltage characteristics per unit thickness. BaTiO 3 ceramic capacitor with smaller grains had higher reliability under the DC bias and higher withstanding voltage per unit thickness due to the shell with para-electricity. The highly accelerated lifetime test showed that the insulation resistance with smaller particle size exhibited one order higher as the voltage increases at higher temperatures and the samples with a size of 500 nm had a sharp drop in insulation resistance at 200 V. Small particles (150, 250 nm) have a smaller product of insulation resistance and capacity than larger particles (500 nm). But, the withstanding voltage per unit thickness of the small particles (150, 250 nm) was 82, 71 V/μm, respectively, which was greater than 58 V/μm of the larger particles (500 nm). This is thought to be an eff ect of suppressing the movement of defects in the smaller particles because small grains have many grain boundaries.
Dielectric Properties of Polymer-ceramic Composites for Embedded Capacitors
Yoon, Jung-Rag,Han, Jeong-Woo,Lee, Kyung-Min The Korean Institute of Electrical and Electronic 2009 Transactions on Electrical and Electronic Material Vol.10 No.4
Ceramic-polymer composites have been investigated for their suitability as embedded capacitor materials because they combine the processing ability of polymers with the desired dielectric properties of ceramics. This paper discusses the dielectric properties of the ceramic ($BaTiO_3$)-polymer (Epoxy) composition as a function of ceramic particle size at a ceramic loading of 40 vol%. The dielectric constant of these ceramic-polymer composites increases as the powder size decreases. Results show that ceramic-polymer composites have a high dielectric constant associated with the $BaTiO_3$ powder with a 200 nm particle size, high insulation resistance, high breakdown voltage (> 22 KV/mm), and low dielectric loss (0.018-0.024) at 1 MHz.
Yoon, Jung-Rag,Moon, Bong Hwa,Lee, Heun Young,Jeong, Dae Yong,Rhie, Dong Hee The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.4
Multilayer capacitors with high ripple current and high capacitance were manufactured. The electrical properties of these capacitors were characterized for potential application for DC-link capacitors in hybrid electric vehicle inverters. Internal electrode structures were designed to achieve high capacitance and reliability. A single multilayer capacitor showed $0.46{\mu}F/cm^3$ of capacitance, 0.65% of dielectric loss, and 1450 V to 1650 V of dielectric breakdown voltage depending on the design of the internal electrode. The capacitor module designed with several multilayer capacitors gave a total capacitance of $450{\mu}F$, which is enough for hybrid electric vehicles. In particular, an equivalent series resistance of $4.5m{\Omega}$ or less will result in 60 $A_{rms}$, thereby reaching the allowed ripple current for hybrid electric vehicles.
Yoon, Jung-Rag,Lee, Chang-Bae,Lee, Kyung-Min,Lee, Heun-Young,Lee, Serk-Won The Korean Institute of Electrical and Electronic 2009 Transactions on Electrical and Electronic Material Vol.10 No.5
The microstructure and the electrical properties of a ZnO varistor, which was composed of a ZnO-$Bi_2O_3$-$Sb_2O_3$-CoO- $MnO_2$ -NiO-$Nd_2O_3$ system, were investigated at various $Y_2O_3$ addition concentrations. $Y_2O_3$ played a role in the inhibition of the grain growth. As the $Y_2O_3$ content increased, the average grain size decreased from $6.8{\mu}m$ to $4{\mu}m$, and the varistor voltage($V_{1mA}$) greatly increased from 275 to 400 V/mm. The nonlinearity coefficient ($\alpha$) decreased from 72 to 65 with increasing $Y_2O_3$ amount. On the other hand, the leakage current ($I_L$) increased from 0.2 to 0.9 ${\mu}A$. These results confirmed that doping the varistors with $Y_2O_3$ is a promising production route for production of a higher fine-grained varistor voltage ($V_{1mA}$) which can dramatically reduce the size of the varistors.
Jung-Rag Yoon,Bong Hwa Moon,Heun Young Lee,Dae Yong Jeong,Dong Hee Rhie 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.4
Multilayer capacitors with high ripple current and high capacitance were manufactured. The electrical properties of these capacitors were characterized for potential application for DC-link capacitors in hybrid electric vehicle inverters. Internal electrode structures were designed to achieve high capacitance and reliability. A single multilayer capacitor showed 0.46 3F/cm₃ of capacitance, 0.65% of dielectric loss, and 1450 V to 1650 V of dielectric breakdown voltage depending on the design of the internal electrode. The capacitor module designed with several multilayer capacitors gave a total capacitance of 450 3F, which is enough for hybrid electric vehicles. In particular, an equivalent series resistance of 4.5 m7 or less will result in 60 Arms, thereby reaching the allowed ripple current for hybrid electric vehicles.
Yoon, Jung-Rag,Lee, Chang-Bae,Lee, Kyung-Min,Lee, Heun-Young,Lee, Serk-Won The Korean Institute of Electrical and Electronic 2010 Transactions on Electrical and Electronic Material Vol.11 No.3
(1-X) $(Na_{0.5}K_{0.5})NbO_3-X$ $K_4CuNb_8O_{23}$ (NKN-X KCN) ceramics were produced using the conventional solid state sintering method, and their sinterability and electric properties were investigated. The density, dielectric constant (${\varepsilon}_r$), piezoelectric constant $d_{33}$, electromechanical coupling factor $k_p$ and mechanical quality factor $Q_m$ value of the NKN ceramics depended upon the KCN content and the sintering temperature. In particular, the KCN addition to the NKN greatly improved the mechanical quality factor $Q_m$ value. The ceramic with X = 2.0 mol% sintered at $1,150^{\circ}C$ possesses the optimum properties (${\varepsilon}_r=241$, $d_{33}=78$, $k_p=0.34$ and $Q_m=1,121$). These results indicate that the ceramic is a promising candidate material for applications in lead free piezoelectric transformer and filter materials.
Yoon, Jung-Rag,Lee, Kyung-Min,Lee, Serk-Won The Korean Institute of Electrical and Electronic 2009 Transactions on Electrical and Electronic Material Vol.10 No.1
The reliability of multilayer ceramic capacitor with active thin dielectric layer was investigated by highly accelerated life test at various stress condition. The distribution of multilayer ceramic capacitor failure times is plotted as a function of time from Weibull distribution function. According to the test result, voltage acceleration factor is obtained from 2.24 to 2.96. The acceleration by temperature is much higher than other values of active thick dielectric layer. It is clear that median time to failure is affected by the stress voltage for high volumetric efficiency ceramic capacitors with active thin dielectric layer. The degradation under stress of voltage involves electromigration and accumulation of oxygen vacancy at Ni electrode interface of cathode.