• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2000년도 종합학술발표회 논문집 Vol.10 No.1
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• pp.243-247
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• 2000

In this parer, Q-factor measurement method for a dielectric resonator in an MIC environment using the effective dielectric constant is proposed. The effective dielectric constant technique is applied to both radial and axial directions. The proposed method shows that the accuracy of the Q-factor measurement is to be improved with 2% ～ 3% relative error.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1738-1745
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• 2015

Radiation characteristics of a probe-fed rectangular microstrip patch antenna printed on a finite grounded high permittivity substrate are investigated systematically for various square grounded dielectric substrate sizes with several thicknesses and dielectric constants by experiment and full wave simulation. The effect of the substrate size on the radiation characteristics of a rectangular patch antenna is mainly determined by the effective dielectric constant of surface waves on a grounded dielectric substrate. As the effective dielectric constant of surface waves increases, the substrate sizes for the maximum broadside gain and the required onset for a large magnitude of squint angle decrease, while the variations of the broadside gain, the front-to-back ratio, and the magnitude of squint angle versus the substrate size increase due to the increase of the power of the surface wave.

• 대한전자공학회논문지
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• 제19권3호
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• pp.13-18
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• 1982

본 논문은 마이크로스트립 선로의 실효 유전률에 관한 실험적인 연구이다. 자유 공간 파장대 관내 파장비의 2승으로 주어지는 실효 유전률을 테프론 유전체판으로 만든 공진기의 공진 현상을 이용하여서 측정하고 이것과 마이로스트립 선로상의 전류 분포를 Fourier 변환하여서 얻은 이론 계산치와를 비교 고찰하여 제작된 원형및 타원형 공진기로 부터 얻어진 실험치와 이론치가 8∼12GHz범위의 X-Band에서 # =1일때 거의 일치하는 결과를 얻을 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3423-3426
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• 2012

Dielectric measurement on binary mixtures of Allyl chloride (ALC) with 2-Pentanone (2-PE) and 2-Hexanone (2-HE) has been carried out over the entire concentration range using Time Domain Reflectometry (TDR) technique at various temperatures in microwave frequency range of 10 MHz to 10 GHz. The static dielectric constant, excess static dielectric constant (${\varepsilon}^E_S$), effective Kirkwood correlation factor ($g^{eff}$) of binary mixtures over entire concentration range were determined to study the effect of increasing alkyl group of ketones on hetero molecular interaction. It was found that magnitude of excess static dielectric constant of mixtures increases with increase of alky group of ketones. The study reveals that the dipole moment of Allyl chloride in mixture have antiparallelism tendency where as 2-pentanone and 2-hexanone have parallelism tendency. Excess static dielectric constant is also fitted to Redlich-Kister equation to get information about rates of multimers formation.

• 마이크로전자및패키징학회지
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• 제11권1호
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• pp.87-96
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• 2004

폴리머/세라믹 복합체는 유기기판용 내장형 커패시터의 가장 유망한 재료다. 폴리머/세라믹 복합체의 유효유전상수를 예측하는 것은 복합재료의 설계에 있어 매우 중요하다. 본 논문에서는 크기가 다른 5가지 $BaTiO_3$ 분말을 이용하여 분말함량에 따른 에폭시/$BaTiO_3$ 복합 내장형 커패시터 필름의 유전상수를 측정하였다. 그 측정 결과를 여러 가지 이론식들에 최소 자승법을 이용해 fitting하여 폴리머/세라믹 복합체의 유효유전상수를 예측하는데 가장 유용한 식을 찾고 BaTiO$_3$ 분말의 유전상수를 추정하고자 하였다. Lichtenecker식과 Jayasundere-Smith식이 에폭시/$BaTiO_3$ 복합 내장형 커패시터 필름의 유전상수 예측에 유용한 것으로 나타났다. 피팅을 통해 계산된 $BaTiO_3$ 분말의 유전상수는 분말의 크기에 따라 100 에서 600 사이였는데 이는 다결정 세라믹 $BaTiO_3$의 유전상수보다 작은 값이다.

• Bulletin of the Korean Chemical Society
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• 제27권5호
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• pp.718-724
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• 2006

The heterogeneous association behaviour of various concentration binary mixtures of mono alkyl ethers of ethylene glycol with ethyl alcohol were investigated by dielectric measurement in benzene solutions over the entire concentration range at 25 ${^{\circ}C}$. The values of static dielectric constant $\epsilon_0$ of the mixtures were measured at 1 MHz using a four terminal dielectric liquid test fixture and precision LCR meter. The high frequency limiting dielectric constant $\epsilon_\infty$ values were determined by measurement of refractive index $n_D$ ($\epsilon_\infty\;=\;n_D\;^2$). The measured values of $\epsilon_0$ and $\epsilon_\infty$ were used to evaluate the values of excess dielectric constant $\epsilon^E$, effective Kirkwood correlation factor $g^{eff}$ and corrective correlation factor $g_f$ of the binary polar mixtures to obtain qualitative and quantitative information about the H-bond complex formation. The non-linear behaviour of the observed $\epsilon_0$ values of the polar molecules and their mixtures in benzene solvent confirms the variation in the associated structures with change in polar mixture constituents concentration and also by dilution in non-polar solvents. Appearance of the maximum in $\epsilon^E$ values at different concentration of the polar mixtures suggest the formation of stable adduct complex, which depends on the molecular size of the mono alkyl ethers of ethylene glycol. Further, the observed $\epsilon^E$ < 0 also confirms the heterogeneous H-bond complex formation reduces the effective number of dipoles in these polar binary mixtures. In benzene solutions these polar molecules shows the maximum reduce in effective number of dipoles at 50 percent dilutions. But ethyl alcohol rich binary polar mixtures in benzene solvent show the maximum reduce in effective number of dipoles in benzene rich solutions.

• 대한전자공학회논문지TC
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• 제41권12호
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• pp.131-137
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• 2004

본 논문에서는 등각사상 법을 이용해 유전체가 다층으로 코팅된 평행 2선식 전송선로의 특성임피던스 및 유효 유전상수 등을 계산하는 방법을 제안하였다. 먼저 두께 및 유전상수가 다른 유전체가 임의의 N 층으로 코팅되었을 때 평행 2선식 전송선로의 정전용량을 계산하였으며, 이를 이용해 임피던스 및 유효 유전상수 등을 계산하였다. Ansoft 사의 Maxwell 2D를 이용한 시뮬레이션 결과와 비교하였을 때, 계산 결과가 오차범위 4% 이내로 거의 일치함을 알 수 있었다.

• 한국세라믹학회지
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• 제30권1호
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• pp.78-84
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• 1993

In PMN-pyrochlore phase mixtures, dielectric constant was measured as a function of the volume fraction of pyrochlore phase and considered with general effective media(GEM) equation. For the application of GEM equation to this system, the critical volume fraction(Vc) where connectivity between the perovskite PMN and pyrochlore phase changed from 0-3 to 3-3, was determined based on the each particle size ratio of two phases with microstructural observation. And then the t value was determined from modified percolation powder-law dependence ( K-Kc (V-Vc)t). In the case of applying such values of t and Vc to the GEM equation, which provided a reasonable fit to the measured dielectric constant within the experimental error range.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.422-424
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• 1996

The dielectric constants of small particles are estimated using negative dielectrophoresis(DEP). A pair of cylindrical electrodes is proposed to produce a non-uniform electric field that levitates a dielectric particle. Measuring the height of the levitated particle, we can calculate the effective polarizability, and estimate the dielectric constant of the particle using a nonlinear regression method. By determining dielectric constant of polystyrene and polychloromethylstyrene particle, the proposed electrode structure and method show the possibility to measure the dielectric constants of dielectric particles.

• Tribology and Lubricants
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• 제37권2호
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• pp.41-47
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• 2021

An experimental device was developed for analysis of hydraulic oil characteristics with dielectric constant sensors. Online analysis is the most effective method of the three methods used for analyzing lubricant oils. This is because it can monitor the machine condition effectively using oil sensors in real time without requiring excellent analysis skill and eliminates human errors. Determining the oil quality usually requires complex laboratory equipment for measuring factors such as density, viscosity, base number, acid number, water content, additive, and wear debris. However, the electric constant is another indicator of oil quality that can be measured on-site. The electric constant is the ratio of the capacitance of a capacitor using that material as a dielectric, compared with a similar capacitor that has a vacuum as its dielectric. The electric constant affects the factors such as the base oil, additive, temperature, electric field frequency, water content, and contaminants. In this study, the tendency of the electric constant is investigated with a variation of temperature, water content, and dust weight. The experimental device can control working temperature and mix the contaminants with oil. A machine condition monitoring program developed to analyze hydraulic oil is described. This program provides graph and digital values with variation of time. Moreover, it includes an alarm system for when the oil condition is bad.