• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.72-75
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• 2000

This paper investigates the complex permittivity of foam materials using the rectangular waveguide. The transmission coefficients of materials inserted in the waveguide are measured with a network analyzer and calculated from the equivalent transmission line model. We use the trial and error method in the acquisition of the complex permittivity.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.67-70
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• 2007

LTCC (Low Temperature Co-fired Ceramic) has been emerged as a promising technology in packaging industry. In this technology the lamination and the sintering process are very important because they change the permittivity of ceramics and the dimension of metal pattern which have influences on electric property. In this paper we studied on influence of the permittivity and the dimension change by lamination pressure and sintering temperature of LTCC process. As a results, permittivity increase along with increasing of lamination pressure and sintering temperature.

• 한국인터넷방송통신학회논문지
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• 제12권2호
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• pp.199-203
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• 2012

평행판 도파관에 진행하는 TEM mode를 이용한 평판형 유전체의 유전율을 측정하는 방식을 소개한다. 이는 양 옆이 열린 구조적 장점으로 실험 절차 및 측정 샘플의 가공이 매우 간편한 장점이 있다. 샘플의 유무에 따라 변화하는 도파관 내에서 전파하는 TEM mode의 위상 속도의 차이를 전자기적으로 해석하였고 이를 이용하여 유전체판의 유전율을 측정하였으며, 샘플에 대한 측정 결과는 기존에 알려진 유전율과 일치하였다.

• 한국세라믹학회지
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• 제29권4호
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• pp.293-297
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• 1992

A proper combination of complex permeability and permittivity is necessary to produce the zero-reflection microwave absorber with an impedance matching. Increasing of dielectric permittivity and development of an impedance matching was investigated in ferrite-rubber composite specimens by addition of conducting materials. Graphite powder of high dielectric constant was added to the composite specimens to increase the permittivity. The precise estimation of graphite content to produce the matched-wave-impedance absorber at a given frequency can be made by using the numerically derived solution map of impedance matching. It was suggested that permittivity adjustment is an effective technique to obtained the microwave absorber with both good absorbing properties and small thickness as well.

• 한국세라믹학회지
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• 제40권4호
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• pp.371-374
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• 2003

Various types of equation for mixing rule on permittivity of mixture have been proposed, but none of these is not perfect because of the inconsistency between the actual geometrical configuration and the basic model for calculation. Serial model and parallel model are lower and upper extremes of mixing manner, the apparent permittivity of any other type of mixture stay between these two extreme states. For the random mixture of the stumpy fine particles, customarily the logarithmic mixing rule has been applied. But, the logarithmic mixing rule does not give the proper value of permittivity in low or high mixing rate of constituent. The author proposed the new mixing rule that gives better consistency with measured value in whole mixing range compared to the logarithmic rule. In this paper, a desirable refinement on the equation proposed in the previous paper is made to adapt to thr configuration image of actual compound and then the equation has been expanded to the complex permittivity to apply the mixing rule on the dissipative materials cases.

• Tribology and Lubricants
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• 제27권3호
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• pp.156-161
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• 2011

The rectangular waveguide technique can be used to measure the complex permittivity of dielectric material of various thickness and cross section. This paper presents the analysis system of engine oil permittivity at which deterioration of engine oil is measured at the X-band(8-12.5 GHz). The middle of the rectangular waveguide has engine oil case and is connected with VNA(Vector Network Analyzer) for the measurement of the transmission$(S_{21})$ and reflection$(S_11)$ and then the permittivity is extracted. The deterioration of engine oil is proved by the comparison with both the extracted data and reference data. As the additional research, This paper suggest that an accurate permittivity is considered by not only the wave guide length but the air gap between oil case and the waveguide.

• Tribology and Lubricants
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• 제27권4호
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• pp.209-212
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• 2011

The capacitive application(prove) can be used to measure the complex permittivity of dielectric material of various thickness and cross section. This paper presents that we designed the analysis system of engine oil permittivity to know the relation between the engine oil deterioration and the prove dimension. Each of the dimension of capacitive prove is changed and then electric capacity is measured by LCR {Inductance(L), Capacitance (C), and Resistance (R)} meter. The engine oil permittivity has extracted in the prove measurement. As the additional research, this paper suggest the best of the prove dimension for the permittivity measurement.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.813-816
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• 2001

In this paper, the dielectric properties of epoxy composites used for transformers are studied. The dielectric permittivity and loss of specimen are measured at the frequency range of 30[Hz]∼1[MHz] about temperature 20[$^{\circ}C$],100[$^{\circ}C$] and 140[$^{\circ}C$] respectively from a series of experiments. When the filler is added, between epoxy and silica is formed interface. Therefore, observed higher values of dielectric permittivity and loss in filled epoxy are attributed to MWS polarization effect. Also, glass transition temperature was shifted to higher temperature and value of dielectric permittivity and loss were decreased due to 2nd curing. Deformation of interfacial state is improved and value of dielectric permittivity and loss were decreased at low frequency region by the surface treatment of fillers with silane coupling agents.

• 소성∙가공
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• 제16권5호통권95호
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• pp.396-400
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• 2007

LTCC(Low Temperature Co-fired Ceramic) which offers a good performance to produce multilayer structures with electronic circuits and components has emerged as an attractive technology in the electronic packaging industry. In LTCC module fabrication process, the lamination and the sintering are very important processes and affect the electrical characteristics of the final products because the processes change the permittivity of ceramics and the dimension of the circuit patterns which have influences on electronic properties. This paper discusses the influence of lamination pressure and sintering temperature on the permittivity and the dimensional change of LTCC products. In the present investigation, it is shown that the permittivity increases along with increasing of the lamination pressure and the sintering temperature.

• 콘크리트학회논문집
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• 제12권3호
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• pp.115-123
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• 2000

Characterizing the electromagnetic properties of concrete is essential to the enhancement of accuracy and reliability in nondestructive testing of concrete structures using electromagnetic techniques. To establish a data base for the properties of concrete, a measurement technique has been developed and a set of data has been obtained for the frequency range of 1~6 GHz. As moisture content is one of major contributing factors to determine permittivity of dielectric material, moisture content is varied during the measurement. An application of a measurement system which consists of open-ended coaxial probe and automatic network analyzer to concrete and mortar specimens is studied. For this, calibration techniques, size of specimens, and number of measurements necessary to obtain reliable data are investigated. From the measured data, it is shown that moisture content plays an important role to determine the permittivity of specimens. As the moisture content increases. The permittivity of specimens show tendency to approach the permittivity of water.