• Title, Summary, Keyword: Permittivity

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The Photon Energy Characteristics of ZnO Thin Film Fabricated by RF Sputtering (RF Sputtering으로 제작한 ZnO 박막의 Photon Energy 특성)

  • Kim, Byung-In;Kim, Won-Bae;Chung, Seong-Gyo;Kim, Duck-Tae;Choi, Young-Il;Kim, Hyung-Gon;Song, Chan-Il
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.73-79
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    • 2002
  • This study evaporates ZnO layer thickness' differently with RF sputtering method on Si Wafer(n-100). This study is performed to examine the characteristics of photon energy and dielectric loss according to the thickness of ZnO and increase the reliability and reproduction of ZnO thin film. It is confirmed that the variation of electric Permittivity by frequency is resulted from the formation of particles within thin film, the particle size and the polarization on grain boundary. Peak of electric Permittivity value of thin film has slower and less value in early low wavelength by the coulomb force involved in carrier combination according to the increase of frequency. Reversal of electric Permittivity values is induced by dipole polarization shown in the dielectric of thin film. Complex electric constant $({\varepsilon}_1,{\varepsilon}_2)$ has larger peak values as it's thickness is thinner and then it is larger according to the increase of frequency. Electric Permittivity by photon energy has large value in imaginary number and is reduced exponentially by the increase of carrier density according to that of photon energy.

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The Performance of Ultra-Wideband Filter with regard to dielectric materials (유전체 특성에 따른 UWB용 필터 특성에 관한 연구)

  • Yoo, Chan-Sei;Lee, Joon-Keun;Jung, Hyun-Chul;Yoo, Myong-Jae;Lee, Woo-Sung;Kang, Nam-Kee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.307-308
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    • 2006
  • In this paper, we propose an ultra wideband pass filter of ring type with embedded stripline stub. The fractional bandwidth was 98 % at the center frequency of 8 GHz and insertion loss was below 1 dB in passband. Two kinds of dielectric materials with the permittivity of 7.8 and 40, respectively were adopted in evaluating the suggested filter structure. As the permittivity of material became larger, the size of filter smaller as expected without any sacrifice in filter performance. In summary, the suggested filter structure has smaller size due to the embedded stripline stub and can be minimized by adopting dielectric material with higher permittivity again.

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Sintering and Microwave Properties of Ba Hexagonal Ferrite (Ba 육방정 페라이트의 소결 특성 및 마이크로파 특성)

  • Kim, Jae-Sik;Ryu, Ki-Won;Bae, Seon-Gi;Lee, Young-Hie
    • Proceedings of the KIEE Conference
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    • pp.1293_1294
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    • 2009
  • The sintering and high frequency electro-magnetic properties of Ba-hexagonal ferrite were investigated. All samples of the Ba-hexagonal ferrite were prepared by the conventional mixed oxide method and sintered at $1150^{\circ}C$~$1400^{\circ}C$. From the X-ray diffraction patterns of sintered Ba-hexagonal ferrite, the $Ba_3Co_2Fe_{24}O_{41}$ phase was represented as main phase in the almost sintering conditions. The bulk densities with sintering temperature and decreased at $1400^{\circ}C$. The permittivity ($\varepsilon$') and loss tangent of permittivity ($\varepsilon$"/$\varepsilon$') of $Ba_3Co_2Fe_{24}O_{41}$ ceramics increased and decreased with sintering temperature, respectively. The permeability of $Ba_3Co_2Fe_{24}O_{41}$ ceramics decreased with sinteirng temperature. The loss tangent of permeability was not changed compared each other with sintering temperature. The bulk density of $Ba_3Co_2Fe_{24}O_{41}$ ceramics sintered at $1300^{\circ}C$ was 4.79 g/$cm^3$. The permittivity, loss tangent of permittivity and permeability, loss tangent of permeability were 19.896, 0.1718 and 14.218, 0.2046 at 210 MHz, respectively.

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Complex Permittivity of Dry Sand Measured by an Open-Ended Coaxial Probe (개방단말 동축선 프로브로 측정된 마른 모래의 복소 유전율)

  • Shin, Hyun;Kim, Se-Yun;Kim, Young-Sik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.37 no.5
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    • pp.17-24
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    • 2000
  • Complex permittivity of dry sand is measured by using an open-ended coaxial probe, which was self-designed and manufactured. As a simple calibration scheme of the probe, the phase difference between the measured and the calculated reflection coefficients of pure water is subtracted from the phase of the measured reflection coefficient for dry sand. And then the complex permittivity of dry sand is reconstructed by applying its measured reflection coefficient into an improved imaginary transmission-line model. The accuracy of our measurement scheme is verified by showing that its reconstructed complex permittivity approaches the precise value of dry sand.

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A Study on the Factors to Influence Permittivity in the Radome Manufacturing Process (레이돔 제조 공정과정에서 유전율에 미치는 영향 인자에 대한 연구)

  • Kang, Shin-Min;Keum, Jong-Ju;Kang, Chun-Ho;Lee, Seung-Jae;Byun, Gi-Sig
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.2
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    • pp.221-226
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    • 2009
  • A nonlinear curve shaped radome should be designed in a way that the deterioration of electrical performance in terms of mechanical strength and radio frequency(RF) can be minimized to protect the antenna. Electrical performance, in particular, is a critical factor that depends on the permittivity of the original materials and thus should be monitored during the manufacturing process along with other factors. This study set out to identify major factors that would affect permittivity during the manufacturing process of a radome through experiments and examine the impacts of permittivity on a radome's electrical performance through simulations.

Electrical Characteristics Assessment for PE Series Insulations (PE 계열 절연재 전기적 특성 평가)

  • Jung, Jong-Wook;Jung, Jin-Soo;Han, Woon-Ki
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.5
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    • pp.430-435
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    • 2007
  • This paper describes the results of electrical characteristics assessment for organic insulations of polyethylene(PE) series insulations and acrylonitrile butadiene styrene copolymer(ABS). In the experiment, 4 kinds of specimens by composition density were tested in relative permittivity, specific resistance and tracking duration. A WinDETA system and a tracking test set manufactured for this assessment were used to measure the dielectric parameters and tracking duration, respectively. In measuring the tracking duration, the time from testing voltage application to testing circuit breaking due to the tracking current was measured. As a result, dielectric dispersion was observed in measuring the relative permittivity of ABS. It was confirmed that the relative permittivity decreased with the density of the PE series insulations and it depends rather on the temperature than frequency. In most specimens, specific resistance exponentially decreased with frequency and the result for each specimen was almost similar. By the way, in the tracking test, all the PE series insulations showed more excellent performance than ABS and especially in the case of HDPE, its tracking withstand performance was the best.

Concentration dependent dielectric properties of Barium Titanate/Polyvenylidene Fluoride (PVDF) and (Bi0.5Na0.5)0.94Ba0.06TiO3/Poly(VDF-TrFE) composite

  • Roy, Ansu K.;Ahmad, Z.;Prasad, A.;Prasad, K.
    • Advances in materials Research
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    • v.1 no.4
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    • pp.285-297
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    • 2012
  • The present study addresses the problem of quantitative prediction of effective complex relative permittivity of Barium Titanate/Polyvenylidene Fluoride (PVDF) and $(Bi_{0.5}Na_{0.5})_{0.94}Ba_{0.06}TiO_3$/Poly(VDF-TrFE) biphasic ceramic-polymer composites. Theoretical results for effective relative permittivity derived from several dielectric mixture equations were fitted to the experimental data taken from the works of Prasad et al. (2010), Wang et al. (2004), Takenaka et al. (1991) and Yamada et al. (1982). The study revealed that out of the different test equations, only a few equations like modified Rother-Lichtenecker equation, Dias-Dasgupta equation or Rao equation for the real part and Bruggeman equation for the imaginary part of complex permittivity well fitted the corresponding experimental results. In the present study, some of the equations were used in their original forms, while some others were modified by choosing suitable shape-dependent parameters in order to get reasonably good agreement with experimental results. Besides, the experimental results have been proposed in the form of a mathematical model using first order exponential growth, which provided excellent fits.

Conversion of Permittivity of PCB Substrate Using Moment Method (모멘트 방법을 사용한 PCB 기판의 유전율 환산)

  • Jung Ji-Hyun;Jo Yu-Sun;Kim Se-Yun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.2
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    • pp.222-227
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    • 2005
  • The permittivity profile of PCB substrate in a wide bandwidth is obtained by applying the moment method to the reflection coefficients measured by an open-ended coaxial probe. In this paper, the relation between a reflection coefficients and the corresponding permittivity is expressed into an integral form and the reflection coefficient of PCB substrates with different thickness are calculated using the dispersive FDTD method. The simulation results assure the validity of our conversion procedure within $2.015\%$ error.

Analysis on Electric Field Based on Three Dimensional Atmospheric Electric Field Apparatus

  • Xing, Hong-yan;He, Gui-xian;Ji, Xin-yuan
    • Journal of Electrical Engineering and Technology
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    • v.13 no.4
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    • pp.1697-1704
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    • 2018
  • As a key component of lighting location system (LLS) for lightning warning, the atmospheric electric field measuring is required to have high accuracy. The Conventional methods of the existent electric field measurement meter can only detect the vertical component of the atmospheric electric field, which cannot acquire the realistic electric field in the thunderstorm. This paper proposed a three dimensional (3D) electric field system for atmospheric electric field measurement, which is capable of three orthogonal directions in X, Y, Z, measuring. By analyzing the relationship between the electric field and the relative permittivity of ground surface, the permittivity is calculated, and an efficiency 3D measurement model is derived. On this basis, a three-dimensional electric field sensor and a permittivity sensor are adopted to detect the spatial electric field. Moreover, the elevation and azimuth of the detected target are calculated, which reveal the location information of the target. Experimental results show that the proposed 3D electric field meter has satisfactory sensitivity to the three components of electric field. Additionally, several observation results in the fair and thunderstorm weather have been presented.

Study on the numerical model of complex permittivity of composites based on the percolation theory (퍼콜레이션 이론에 기초한 복합재료의 복소 유전율 모델에 대한 연구)

  • Kim, Jin-Bong;Lee, Sang-Kwan;Kim, Chun-Gon
    • Composites Research
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    • v.22 no.3
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    • pp.44-54
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    • 2009
  • In this paper, we proposed a numerical model the complex permittivity for the E-glass fabric/epoxy composite laminate containing electrical conductive carbon black. The model is based on the percolation theory and for the composites over than the percolation threshold and in higher frequency band in that the AC conductivity is fully proportional to the frequency. The measurement for the complex permittivity wasperformed at the frequency band of 0.5 GHz $\sim$ 18.0 GHz using a vector network analyzer with a 7 mm coaxial air line. The proposed model is composed of the numerical equations of the scaling law used in percolation theory and constants obtained from experiments to quantify the model itself. The model describes the complex permittivity as the function of frequency and filler concentration. The model was verified by being compared with the measurements.