• Title/Summary/Keyword: EM Wave Absorption

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Development of Electromagnetic Wave Absorbers Using Sendust for a Portable Phone (Sendust를 이용한 휴대전화용 전파흡수체의 개발)

  • Choi, Jung-Hyun;Kim, Dong-Il;Song, Jae-Man;Jung, Jae-Hyun
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.06a
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    • pp.429-434
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    • 2005
  • In this paper, we investigated EM wave absorption property of EM wave absorbers prepared with sendust. The EM wave absorbers have good EM wave absorption properties in 1 GHz ${\sim}$ 3 GHz. On the other hand, the absorption band of the EM wave absorber coated with $Al(OH)_3$ larger than non-coated one. Pulverization effect of sendust on EM wave absorption properties was also investigated.

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A Study on Multi-Layered EM Wave Absorber Using Natural Lacquer as a Binder

  • Choi, Dong-Han;Kim, Dong-Il;Choi, Chang-Mook;Li, Rui
    • Journal of Navigation and Port Research
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    • v.30 no.9
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    • pp.767-772
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    • 2006
  • Generally, a silicone rubber and a chlorinated polyethylene(CPE) have been used as a binder for the development of high-performance composite EM(Electro Magnetic) wave absorbers. In this paper, the EM wave absorption performance of natural lacquer, which is newly proposed as a binder was investigated. The prepared MnZn ferrite EM wave absorbers are mixed with natural lacquer showed excellent EM wave absorption characteristics compared with MnZn ferrite EM wave absorbers which are mixed with the conventional binders. MnZn ferrite EM wave absorbers mixed with natural lacquer were prepared and their absorption ability was also investigated The EM wave absorbers are fabricated in different proportions of MnZn, or NiZn ferrite and natural lacquer, and their reflection coefficients are measured. The permittivity and permeability are calculated by using the measured reflection coefficients. The EM wave absorption abilities are calculated according to different thicknesses of the EM wave absorbers.

A Study on Multi-Layered EM Wave Absorber Using Natural Lacquer as a Binder

  • Choi, Dong-Han;Kim, Dong-Il;Choi, Chang-Mook;Li, Rui
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.157-161
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    • 2006
  • Generally, a silicone rubber and a chlorinated polyethylene(CPE) have been used as a binder for the development of high-performance composite EM(Electro Magnetic) wave absorbers. In this paper, the EM wave absorption performance of natural lacquer, which is newly proposed as a binder was investigated. The prepared MnZn ferrite EM wave absorbers are mixed with natural lacquer showed excellent EM wave absorption characteristics compared with MnZn ferrite EM wave absorbers which are mixed with the conventional binders. MnZn ferrite EM wave absorbers mixed with natural lacquer were prepared and their absorption ability was also investigated. The EM wave absorbers are fabricated in different proportions of MnZn, or NiZn ferrite and natural lacquer, and their reflection coefficients are measured. The permittivity and permeability are calculated by using the measured reflection coefficients. The EM wave absorption abilities are calculated according to different thicknesses of the EM wave absorbers.

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A Study on Composite EM Absorber's Absorption Characteristics Using Natural Lacquer by Binder (옻을 지지재로 사용한 복합형 전자파 흡수체의 흡수 특성에 관한 연구)

  • Choi, Dong-Han
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2003.11a
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    • pp.622-629
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    • 2003
  • Generally, a silicone rubber and a chloride polyethylene(CPE) have been used for the development of high-performance composite EM(ElectroMagnetic) wave absorber. In this study, the EM wave absorption abilities for natural lacquer which is newly suggested in this study as a binder for composite EM wave absorber were investigated to develop an improved EM wave absorber In addition, MnZn ferrite composite EM wave absorber mixed with the natural lacquer were prepared and their absorption ability was also investigated. MnZn ferrite composite EM wave absorber which employs the natural lacquer as a binder showed an improved EM wave absorption characteristics in comparison with the conventional binder such as a silicone rubber and a chloride polyethylene(CPE). The matching frequency and the absorption ability of EM wave absorber mixed with natural lacquer can be controled the change of the thickness of them.

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Development of EM Wave Absorber for Hi-pass System Using Amorphous Metal Powder

  • Kim, Dong-Il;Yoo, Gun-Suk;Choi, Dong-Soo
    • Journal of Navigation and Port Research
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    • v.35 no.9
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    • pp.717-720
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    • 2011
  • In this paper, we designed and fabricated the Electromagnetic(EM) wave absorber for an Electronic Toll Collection(ETC or Hi-pass) system by using Amorphous metal powder and CPE. The material properties and the absorption properties of the samples containing 50 wt.%, 60 wt.%, 70 wt.%, and 80 wt.% of Amorphous. Moreover, the EM wave absorption abilities were simulated for the different thicknesses of the EM absorbers by adopting the measured permittivity and permeability, and then the EM wave absorber was fabricated based on the simulated design values. As a result, the EM wave absorber with the composition of Amorphous metal powder : CPE = 50 : 50 wt.% with the thickness of 2.6 mm has excellent absorption ability more than 40 dB at 5.8 GHz.

A Study on FDTD Analysis and Fabrication of the Sheet-type Millimeter EM wave Absorber

  • Kim, Dae-Hun;Soo, Dong-Soo;Kim, Dong-Il
    • Journal of Navigation and Port Research
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    • v.34 no.4
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    • pp.299-304
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    • 2010
  • In this paper, the EM wave absorber was developed for the 94-GHz detecting radar system. To analysis an EM wave absorber in millimeter wave band, we fabricated three absorber samples using carbon black and titanium dioxide and permalloy with chlorinated polyethylene. After measuring the complex relative permittivity, the absorption characteristics are simulated by 1D FDTD according to different thicknesses of less than 1.0 mm. Then, the EM wave absorber was fabricated based on the FDTD simulation. As a result, the measured results agreed well with the simulated ones, and the developed EM wave absorber with a thickness of 0.7 mm had the desired absorption characteristics of more than 14 dB in the frequency range of the 94-GHz band.

A Study on Development of EM Wave Absorber Using TiO2 for Automotive Radar in Cars

  • Choi, Chang-Mook;Kim, Dong-Il
    • Journal of electromagnetic engineering and science
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    • v.8 no.3
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    • pp.110-113
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    • 2008
  • In this paper, we designed and fabricated an electromagnetic(EM) wave absorber for automotive radar in cars using $TiO_2$ as a dielectric material and chlorinated polyethylene(CPE) as a binder. First of all, we confirmed that the optimum composition ratio of $TiO_2$ was about 70 wt.%. The complex relative permittivity of a sample containing $TiO_2$: CPE=70:30 wt.% was calculated from S-parameter. The EM wave absorption abilities were simulated for the EM wave absorbers of different thickness using the calculated relative permittivity, and the EM wave absorber was manufactured based on the simulated design. A comparison of simulated and measured results is in good agreement. Measurement shows that a 1.85 mm thick absorber has absorption ability higher than 20 dB in the frequency range of $76{\sim}77$ GHz for automotive radars.

A Study on Development of EM Wave Absorbers for Mobile Phones (휴대전화 단말기용 전파흡수체의 개발에 관한 연구)

  • Jung, Jae-Hyun;Kim, Dong-Il
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.11a
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    • pp.67-68
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    • 2005
  • This thesis is concerned with basic research for development of EM wave absorbers in sheet type for mobile phones. By controlling the sendust ratio, the $Al(OH)_3$ coating, the thickness, the kind of binders, EM wave absorbers were prepared and examined. Centeral frequency shifts toward lower with increasing thickness of the absorber, and absorption ability controlled to adjust Sendust amount. The absorption band of the EM wave absorber coated with $Al(OH)_3$ becomes larger than that of non-coated one. Sendust composite microwave absorbers mixed with CPE were prepared at $70^{\circ}C$ in temperature. The fabricated EM wave absorbers show a reflection coefficient 5.56 dB at 1.8 GHz in thickness of 0.85 mm.

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An Analysis of Natural Lacquer Characteristics and EM Absorber's Absorption Characteristics Using Natural Lacquer by Binder (옻의 특징과 옻을 지지재로 사용한 전자파 흡수체의 두께에 따른 흡수 특성 분석)

  • 최동한;김동일;김기만
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.04a
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    • pp.29-34
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    • 2004
  • Generally, a silicone rubber and a chloride polyethylene(CPE) have been used for the development of high-performance composite EM(ElectroMagnetic) wave absorbers. In this study, the EM wave absorption abilities for natural lacquer which is newly suggested in this study as a binder for composite EM wave absorbers were investigated to develop an improved EM wave absorbers. In addition, MnZn ferrite composite EM wave absorbers mixed with the natural lacquer were prepared and their absorption ability was also investigated. MnZn ferrite composite EM wave absorbers which employs the natural lacquer as a binder showed an improved EM wave absorption characteristics in comparison with the conventional binder such as a silicone rubber and a chloride polyethylene(CPE). The matching frequency and the absorption ability of EM wave absorbers mixed with natural lacquer can be controled the change of the thickness of them.

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A Study on the EM Wave Absorber for Improving Electromagnetic Environment of Wireless LAN at 2.4 GHz

  • Yoo, Gun-Suk;Kim, Dong-Il;Choi, Dong-Soo;Choi, Dong-Han
    • Journal of Navigation and Port Research
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    • v.34 no.7
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    • pp.539-542
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    • 2010
  • In this paper, we designed and fabricated the Electro-Magnetic (EM) wave absorber for wireless LAN by using Amorphous and CPE. The material constants and the absorption properties were measured for the samples containing 50 %, 60 %, and 70 % weight fraction of Amorphous. Moreover, the EM wave absorption abilities were simulated for the EM absorbers in different thicknesses by adopting the measured permittivity and permeability, and then the EM wave absorber was fabricated based on the simulated design values. As a result, the EM wave absorber with the composition ratio in Amorphous : CPE = 60 : 40 wt.% with the thickness of 4 mm has the absorption ability more than 35 dB at 2.4 GHz. Thus, it is expected the wireless LAN environment can be improved by using the developed absorber.