• Title, Summary, Keyword: Relative permittivity

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A Measurement of Electromagnetic Property of Illite found in Young-dong Area (영동산 일라이트의 전자기적 특성 측정)

  • Kim, Jin-Chul;Lee, Won-Hui;Koo,K.W.;Hur, Jung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.267-270
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    • 2000
  • This paper describes measurement of relative permittivity of illite found in young-dong area. A measurement of relative permittivity of illite used to cylindrical cavity resonators with moveable cap. A concentric dielectric-rod inserted cylindrical cavity resonator and an exact field representation of travelling wave mode are introduced for measurement of relative permittivity. The exact electromagnetic fields in cylindrical cavity with concentric dielectric rod is analysed. A relative permittivity of dielectric in cavity is calculated by analyzing the characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. We know that the field representation of travelling mode is exact. As a result, relative permittivity of dielectric materials were 7.820 at sample-1 and 7.894 at sample-2.

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Analysis of the Grounding Impedance of a Ground Rod Considering the Frequency-Dependent Resistivity and Relative Permittivity of Soil (토양의 저항률 및 비유전율의 주파수의존성을 고려한 접지봉의 접지임피던스의 해석)

  • Ahn, Chang-Hwan;Choi, Jong-Hyuk;Lee, Bok-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.1
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    • pp.54-60
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    • 2012
  • When the transient current with high frequency components such as lightning surges are injected the grounding electrodes, the performance of grounding electrodes should be evaluated as grounding impedance. It is restricted to analyze the grounding impedance by measurement approach since the grounding impedance is very different with the shape and size of grounding electrodes, resistivity and relative permittivity of soil and the frequency component of the injected current. So a variety of simulation approaches have been developed. Typically, the soil resistivity measured with low frequency and relative permittivity between 1 and 80 are used for simulation of the grounding impedance. However, the resistivity and relative permittivity of soil are changed with frequency of injected current. In this paper, the frequency-dependent resistivity and relative permittivity of soil are measured and these parameters are reflected in the simulation of the grounding impedance of a ground rod. The simulated results are compared with the measured results. As a result, the simulated results with frequency-dependent soil parameters show capacitive aspect like measured results in the frequency of lower than 100[kHz] and they are more consistent with the measured results in wide frequency range.

Relative Permittivity of Damaged Concrete Bridge Deck According to the Weather Conditions : A Case Study (기상조건에 따른 손상 교량 바닥판의 상대유전율 변화 고찰)

  • Rhee, Ji-Young;Choi, Jae-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.4
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    • pp.209-215
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    • 2017
  • Ground Penetrating Radar (GPR) was applied to an evaluation of the concrete condition of bridge decks with asphalt concrete. Deterioration was considered to have occurred when the relative permittivity of a concrete-faced asphalt concrete overlay showed more than 12. The relative permittivity of concrete varied considerably with the levels of porosity and water. In this study, GPR tests were carried out to determine the influence of weather and concrete condition on the relative permittivity for the research subject of an overlaid concrete bridge deck in public service. According to the test results, if bridge decks are in good condition, the relative permittivity of the top concrete of a bridge deck exhibited a normal distribution. After the deck concrete deteriorated, the relative permittivity varied with the amount of penetrated water according to the weather condition and deteriorated status of deck concrete.

A study on the measuring of relative permittivity of microwave PCB with frequency for the numerical analysis of EMI (EMI 수치해석을 위한 주파수에 따른 마이크로파 인쇄회로기판의 비유전율의 측정에 관한 연구)

  • Jang, In-Bum;Kim, Yong-Chun;Kim, Chung-Heok;Lee, Joon-Ung
    • Proceedings of the KIEE Conference
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    • pp.308-310
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    • 1997
  • In this paper, to anlayze electromagnetic distribution, measure the variation of relative permittivity of Glass-epoxy substrate for Computer-main-board and Tenon substrate for handphone or PCS in the frequency range $100[MHz]{\sim}1[GHz]$, in room temperature. To measure relative permittivity, suggested the Microstripline method. As the frequency increase, the variation of relative permittivity of Glass-epoxy is bigger than Tefoln's. And simulate the electromagnetic distribution on the PCBs in the infinite region applying the open boundary condition with these results by Finite Element Method.

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A Fabrication of From and a Measurement of Relative Permittivity of Illite Found in Young-dong Area (영동산 일라이트의 성형 및 비유전율 측정)

  • Lee, Won-Hui;Choi, Hong-Ju;Koo, Kyung-Wan;hur, Jung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.5
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    • pp.747-754
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    • 2001
  • This paper describes measurement of relative permittivity of illite found in young-dong area. A measurement of relative permittivity of the illite was made using cylindrical cavity resonators with a moveable cap. A concentric dielectric-rod inserted the cylindrical cavity resonator and an exact field representation of non-decaying mode of the resonator are introduced for the measurement of relative permittivity. The exact electromagnetic fields in cylindrical cavity with a concentric dielectric rod is analysed. The relative permittivity of dielectric in the cavity is calculated by analyzing a characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. We know that the field representation of non-decaying mode is exact. As a result, the relative permittivity of dielectric materials was 7.820 for a sample with binder and 7.894 for a pure sample.

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Error Analysis for Microwave Permittivity Measurement using Post Resonator Method (Post Resonator 방법에 의한 마이크로파 유전율 측정에서의 오차 분석)

  • Cho, Mun-Seong;Lim, Donggun;Park, Jae-Hwan;Park, Jae-Gwan
    • Journal of the Microelectronics and Packaging Society
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    • v.19 no.3
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    • pp.43-48
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    • 2012
  • Errors of relative permittivity calculation caused by the variation of sample aspect ratio (diameter/height) and measuring geometry were analyzed by computer simulation and measurement. Firstly, the $S_{21}$ spectrum of the sample (permittivity 38) was simulated in the post resonator measuring apparatus by HFSS simulation. Then, the relative permittivity was calculated from the $TE_{011}$ mode resonant frequency. The relative permittivity varied by ca. 0.3% with sample aspect ratio variation (D/H=0.8~1.6). The relative permittivity varied by ca. 1~10% when the 1~10% of air-gap was introduced in between the dielectric disk and upper conductor. All the simulation results showed consistent tendency with real measurement.

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.

Microwave Dielectric Properties of ZST Ceramics for Mobile Telecommunication System (기지국용 ZST세라믹스의 소결조건에 따른 고주파 유전 특성)

  • 서정철;이희영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.636-639
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    • 2000
  • Effects of sintering temperature and time on relative permittivity $\varepsilon$$\_$r/, unloaded quality factor Q$.$f and temperature coefficient of resonant frequency $\tau$$\_$f/ of dielectric resonator materials produced from commercial ZST powder were investigated in some detail. Q$.$f values, as determined from cavity perturbation method at 1.6 GHz, gradually increased with sintering temperature reaching the maximum at 1420$^{\circ}C$. However, bulk density and relative permittivity values, which increased with temperature, started to decrease above 1380$^{\circ}C$. In addition, Q$.$f values slightly increased with sintering time at the sintering temperature of 1300$^{\circ}C$∼1380$^{\circ}C$, while bulk density and relative permittivity values were approximately constant. It was also found that $\tau$$\_$f/ values were not affected by sintering temperature and time within the experimental conditions used.

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Development of Broad-Band Electromagnetic Wave Absorber for X-band Sensors in Double-layered Type Using Carbon

  • Choi, Chang-Mook;Kim, Dong-Il;Choi, Dong-Han;Li, Rui
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.297-300
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    • 2006
  • In this paper, the EM wave absorbers were designed and fabricated for X-band sensors using Carbon of dielectric material with CPE. The complex relative permittivity of samples is calculated by the measured S-parameter data. We simulated the double-layered type EM wave absorber with broad bandwidth using the measured complex relative permittivity by changing the thickness and layer, which was fabricated based on the simulated design. The fabricated EM wave absorber consist of 1mm first layer sheet facing metal with Carbon composition ratio 70 vol% and 1.5 mm second layer sheet with Carbon composition ratio 60 vol%. The comparisons of simulated and measured results are good agreement. As a result, the optimized absorption ability of double-layered type EM wave absorber with thickness of 2.5 mm is higher than 10 dB from 7.8 GHz to 13.3 GHz.

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The Dielectric Analysis of Insulators for Home Appliances (가전설비용 절연재의 유전열 분석)

  • Jung, Jin-Soo;Jung, Jong-Wook;Yi, Gun-Ho;Bae, Seok-Myung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.206-207
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    • 2006
  • This paper describes the dielectric analysis of several insulators for home appliances. The dielectric characteristics of ABS(acrylonitrile butadiene styrene) were tested in relative permittivity, dielectric loss($tan{\delta}$) and specific resistance and compared with those of the other 4 insulators of PE(polyethylene) series. As a result, the relative permittivity of only the ABS slightly decreased with temperature. In the case of the tan6, the ABS showed higher dielectric loss than the other insulators but more excellent thermal performance. In addition, its changing pattern in specific resistance was very similar to that in $tan{\delta}$.

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