• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.119-122
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• 2003

This paper describes characteristics for insertion losses of Isolator have an effect on material parameter. One purpose of the paper is to present insertion loss on this resonator for magnetic loss, dielectric loss, magnetic field and saturation magnetization. Another is to study the effect of propeller resonator on response characteristics. In this paper, the analysis and measurement of the response characteristics were carried out for the isolator prototype. The measurement results agreed on the simulation results and acquire insertion loss $0.18\;{\sim}\;0.24dB$, return loss 27dB, isolation 27dB and bandwidth 500MHz on this condition saturation magnetization 550G, dielectric loss 0.0004, magnetic loss 20 and dielectric constant 14.

• 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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.73-77
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• 2008

We have investigated dielectric polarization in organic light-emitting diodes using 8-hydroxyquinoline aluminum($Alq_3$) as an electron transport and emissive material. We analyzed the dielectric polarization of organic light-emitting diodes using characteristics of impedance and equivalent circuit of $ITO/Alq_3/Al$. Impedance characteristics was measured complex impedance Z and phase ${\theta}$ in the frequency range of $1{\times}40Hz\;to\;1{\times}10^8Hz$. We obtained complex electrical conductivity, dielectric constant, and loss tangent(tan${\delta}$) of the device at room temperature. And, we obtained the equivalent circuit of $ITO/Alq_3/Al$ through analyzing dielectric constant and dielectric loss tangent. From these analyses, we could interpret a conduction mechanism and dielectric polarization.

• Applied Science and Convergence Technology
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• v.25 no.4
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• pp.77-80
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• 2016

The $PbSc_{1/2}Nb_{1/2}O_3$ ceramics at a relatively low temperature of $1300^{\circ}C$ was successful synthesized. Solid state reaction of two-step process is not necessary. The dielectric constant, dielectric loss and admittance of ceramic samples were determined. The pyroelectric characteristics are in good agreement with the dielectric properties. Ferroelectric properties of well-formed the $PbSc_{1/2}Nb_{1/2}O_3$ ceramics are in agreement with broad distribution of relaxation phenomenon. Relatively strong frequency dependent of dielectric constant is observed at about $110^{\circ}C$. The distinct thermal hysteresis was observed in the measurement of the dielectric constant and dielectric loss. The critical exponents of during cooling and heating measurements in the $PbSc_{1/2}Nb_{1/2}O_3$ ceramics were 1.14 and 1.59 at 1 kHz, respectively.

• Proceedings of the KIEE Conference
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• 2001.07c
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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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.490-491
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• 2007

We have investigated dielectric dispersion and absorption in organic light-emitting diodes using 8-hydroxyquinoline aluminum($Alq_3$) as an electron transport and emissive material. We analyzed the dielectric dispersion and absorption of organic light emitting diodes using impedance characteristics measurement by the auto-balancing bridge technique of ITO/$Alq_3$/Al. Impedance characteristics was measured complex impedance Z and phase e in the frequency range of 40Hz to $10^8Hz$. We obtained dielectric constant and loss tangent (tan $\delta$) of the device. From these analyses, we are able to interpret a dielectric dispersion and dielectric absorption contributed by an interfacial and orientational polarization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.207-209
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• 2004

Currently, for satisfying the needs of scaled MOSFET's a high quality thin oxide dielectric is desired because the properties of conventional $SiO_2$ film are not acceptable for these very small sized transistors. As an alternative gate dielectric have drawn considerable alternation due to their superior performance and reliability properties over conventional $SiO_2$, to obtain the superior characteristics of ultra thin dielectric films, $N_2O$ grown thin oxynitride has been proposed as a dielectric growtuanneal ambient. In this study the authors observed process characteristics of $N_2O$ grown thin dielectric. In view points of the process characteristics of MOS capacitor, the sheet resistance of 4.07$[\Omega/sq.]$, the film stress of $1.009e^{10}[dyne/cm^2]$, the threshold voltage$(V_t)$ of 0.39[V], the breakdown voltage(BV[V]) of 11.45[V] was measured in PMOS. I could achieve improved electrical characteristics and reliability for deep submicron MOSFET devices with $N_2O$ thin oxide.

• Electrical & Electronic Materials
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• v.10 no.3
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• pp.239-246
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• 1997

The ZnO is stabilize dielectric constant over a broad temperature range because its addition makes the relaxation time short. In this study, the composite oxide material (B $a_{0.85}$ $Ca_{0.15}$)Ti $O_{3}$ was mixed by ZnO additive material and the dielectric polarization characteristics was studied. The relative density was over 90[%] at all specimen in the structural characteristics. Among of the specimen, the relative density of (B $a_{0.85}$ $Ca_{0.15}$)Ti $O_{3}$ with ZnO (0.4mol) has a 95[%]. The grain size of composite oxide material with an increasing ZnO increased and it was 1.0[.mu.m]-1.22[.mu.m]. In the electrical characteristics, the charge and discharge current was increased by ZnO addition. The dielectric relaxation time was increased by space charge polarization at above 110[.deg. C] and the dielectric relaxation time was fixed by space charge polarization of para-dielectric layer at below 110[.deg. C]. The dielectric relaxation time was maximum when the grain size was small. The dielectric relaxation time is decreased with an additive material ZnO and interface polarization, existing void at the grain and grain boundary. The remnant polarization is increased and the coercive electric field is decreased by ZnO.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1337-1345
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• 2018

The reliability of power transmission and distribution depends up on the consistency of insulation in the high voltage power transformer. In recent times, considering the drawbacks of conventional mineral oils such as poor biodegradability and poor fire safety level, several research works are being carried out on natural ester based nanofluids. Earlier research works show that sunflower oil has similar dielectric characteristics compared with mineral oil. BIOTEMP oil which is now commercially available in the market for transformers is based on sunflower oil. Addition of nanofillers in the base oil improves the dielectric characteristics of liquid insulation. Only few results are available in the literature about the insulation characteristics of nano modified natural esters. Hence understanding the influence of addition of nanofillers in the dielectric properties of sunflower oil and collecting the database is important. Considering these facts, present work contributes to investigate the important characteristics such as partial discharge, lightning impulse, breakdown strength, tandelta, volume resistivity, viscosity and thermal characteristics of $SiO_2$ nano modified sunflower oil with different wt% concentration of nano filler material varied from 0.01wt% to 0.1wt%. From the obtained results, nano modified sunflower oil shows better performance than virgin sunflower oil and hence it may be a suitable candidate for power transformer applications.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.8
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• pp.323-330
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• 1985

Dielectric loss tangent and ac dielectric strength of GFRP (Glass Fiber Reinforced Plastics, G-10)was investigated as parameters of mechanical and thermal stresses, in order to study the basic dielectrical characteristics of composite insulating materials. The dielectric loss tangent was increased and the ac dielectric strength was decreased with increase in the mechanical stresses beyond the mechanical yield point on account of fiber-matrix debonding, but the dielectric constant was not varied sigificantly. the dielectric strength of G-10 was about 2 MV/cm and the dielectric constant was about 4.8.