• Title/Summary/Keyword: 전파흡수체

Search Result 202, Processing Time 0.023 seconds

Study on Design and Performance of Microwave Absorbers of Carbon Nanotube Composite Laminates (탄소나노튜브 복합재 적층판을 활용한 전파흡수체의 설계 및 성능에 대한 연구)

  • Kim, Jin-Bong;Kim, Chun-Gon
    • Composites Research
    • /
    • v.24 no.2
    • /
    • pp.38-45
    • /
    • 2011
  • In this paper, we present an optimization method for the single Dallenbach-layer type microwave absorbers composed of E-glass fabric/epoxy composite laminates. The composite prepreg containing carbon nanotubes (CNT) was used to control the electrical property of the composites laminates. The design technology using the genetic algorithm was used to get the optimal thicknesses of the laminates and the filler contents at various center frequencies, for which the numerical model of the complex permittivity of the composite laminate was incorporated. In the optimal design results, the content of CNT increased in proportion to the center frequency, but, on the contrary, the thickness of the microwave absorbers decreased. The permittivity and reflection loss are measured using vector network analyzer and 7 mm coaxial airline. The influence of the mismatches in between measurement and prediction of the thickness and the complex permittivity caused the shift of the center frequency, blunting of the peak at the center frequency and the reduction of the absorbing bandwidth.

Development of Multi-layer Electromagnetic wave Absorbers Using Sendust (센더스트를 이용한 적층형 전파흡수체의 개발)

  • Ryu, Jae-Min;Kim, Dong-Ll;Che, Seung-Hun
    • Journal of Navigation and Port Research
    • /
    • v.30 no.8 s.114
    • /
    • pp.637-642
    • /
    • 2006
  • In this paper, we made an experiment on materials of two kinds. First, we made a study of Multi-layer EM wave absorbers using Sendust. In result, The bandwidth of the Multi-layer Sendust EM wave absorbers over 10 dB is extended in S-Band. Second, we investigated the mixing effects of AI(OH)3 on Multi-layer Sendust EM wave Absorbers. In result, the Multi-layer Sendust EM wave absorbers mixed with Al(OH)3 showed a extended bandwidth over 10 dB compared with non-mixed Multi-layer Sendust EM wave absorbers in S-Band.

Development of Multi-layer Electromagnetic wave Absorbers Using Sendust (Sendust를 이용한 적층형 전파흡수체의 개발)

  • Ryu Jae-Min;Kim Dong-Il;Che Seung-Hun
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
    • /
    • 2006.06b
    • /
    • pp.97-101
    • /
    • 2006
  • In this paper, Multi-layer EM wave absorbers using Sendust are presented. The bandwidth of the Multi-layer Sendust EM wave absorbers over 10 dB is extended in S-Band And we investigated the mixing effects of $Al(OH)_3$ on Multi-layer Sendust EM wave Absorbers. As a result, the Multi-layer Sendust EM wave absorbers mixed with $Al(OH)_3$ showed a extended bandwidth over 10 dB compared with non-mixed Multi-layer Sendust EM wave absorbers in S-Band.

  • PDF

Development of EM Wave Absorber for Countermeasure against EM Wave Environment of 2.4 GHz Wireless LAN (2.4 GHz 무선LAN 전자파 환경대책용 전파흡수체 개발)

  • Yoon, Sang-Gil;Kim, Dae-Hun;Park, Soo-Hoon;Kim, Dong-Il
    • Journal of Navigation and Port Research
    • /
    • v.33 no.3
    • /
    • pp.193-197
    • /
    • 2009
  • In this paper, the EM wave absorber was designed and fabricated for improvement of Wireless LAN environment at 2.4 GHz. We fabricated several samples in different composition ratios of Sendust and CPE(Chlorinated Polyethylene). Absorption abilities were simulated in accordance with different thicknesses of the prepared absorbers and changed complex relative permittivity and permeability due to composition ratio. The mixing ratio of Sendust and CPE was searched as 80: 20 wt.% by experiments and simulation Then the EM wave absorber was fabricated and tested using the simulated data. As a result, the EM wave absorber was fabricated based on simulated data. Simulated and measured results agreed well. As a result, the developed EM wave absorber with thickness of 3.25 mm has absorption ability of 19 dB at 2.4 GHz.

Absorption Properties of Thin Permalloy-Rubber Absorbers in Mobile Telecommunication Frequency Bands (Permalloy를 이용한 이동통신주파수 대역용 박형 전파흡수체의 제조 및 특성 연구)

  • Kim, Moon-Suk;Min, Eui-Hong;Koh, Jae-Gui
    • Journal of the Korean Magnetics Society
    • /
    • v.18 no.3
    • /
    • pp.115-119
    • /
    • 2008
  • The raw materials of permalloy were processed the ball-mill for 30 hours and the shape of permalloy particles was changed from sphere to flake type, which was observed using scanning electron microscope. The complex permittivity and permeability spectra and reflection loss of permalloy-rubber composite was measured using Network Analyzer in order to investigate the relationship between the microwave absorption and the material constants. The flake type permalloy-rubber composite showed high reflection loss, which was due to the high complex permittivity and permeability. Also, the matching frequency shifted toward lower frequency range with microwave absorber thickness, and the maximum reflection loss of -6.1 dB was observed in $1.65\;GHz{\sim}1.86\;GHz$ for a 1.3 mm thickness.

Development and prospect of Smart EMW Absorber for Protection of Electronic Circuits and Devices with Heat Radiating Function (전자회로 및 부품 보호용 방열기능형 스마트 전파 흡수체의 개발과 전망)

  • Kim, Dong Il;Park, Soo Hoon;Joo, Yang Ick
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.19 no.5
    • /
    • pp.1040-1046
    • /
    • 2015
  • With the rapid progress of electronics and radio communication technology, human enjoys greater freedom in information communication. However, EMW (Electro-Magnetic Wave) environments have become more complicate and difficult to control. Thus, international organizations, such as the American National Standard Institution (ANSI), Federal Communications Commission (FCC), the Comite Internationale Special des Perturbations Radio Electrique (CISPR), etc, have provided standard for controlling the EM wave environments and for the countermeasure of the electromagnetic compatibility (EMC). In this paper, the status of EMW absorbers and the goal of smart EMW absorber in the future were described. Furthermore, design method of the smart EM wave absorber with heat radiating function was suggested. The designed smart EM wave absorber has the absorption ability of more than 20 dB from 2 GHz to 2.45 GHz band, the optimum aperture (hole) size, the adjacent hole space, and the thickness of which were 6 mm, 9 mm, and 6.5 mm, respectively. Thus, it is respected that these results can be applied as various EMC devices in electronic, communication, and controlling systems.

Development of Electromagnetic Wave Absorbers far Mobile Phone Using Sendust (Sendust를 이용한 휴대전화용 전파 흡수체의 개발)

  • Choi Jung-Hyun;Kim Dong-Il;Song Jae-Man;Jung Jae-Hyun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.16 no.8 s.99
    • /
    • pp.842-847
    • /
    • 2005
  • In this paper, we fabricated sheet-type EM wave absorbers for mobile phones by using sendusts and tested EM wave absorption of it. The band-width of EM wave absorbers coated with $Al_2O_3$ were larger than non-coated EM wave absorbers. Particle size decreased with increasing milling time, which made the result of increasing of EM wave absorption. The fabricated EM wave absorbers show a reflection coefficient 17.4 dB at 946 MHz for a 4 mm sample and 5 dB at 1.8 GHz for a 1 mm sample.

Development of the EM Wave Absorber for ETC of ITS (ITS의 ETC용 전파흡수체 개발)

  • Song, Young-Man;Choi, Chang-Mook;Lee, Dae-Hee;Kim, Dong-Il
    • Journal of Navigation and Port Research
    • /
    • v.31 no.8
    • /
    • pp.671-674
    • /
    • 2007
  • In this paper, the EM wave absorber was designed and fabricated for ETC system, because ETC system has some problems including signal error and system-to-system interference. We fabricated some samples in different composition ratio of MnZn-ferrite, Carbon and CPE, confirmed that optimum composition ratio of Mn2n-ferrite, Carbon, CPE was 40 : 15 : 45 wt%. Complex relative permittivity and complex relative permeability was calculated by the measured data. And absorption abilities were simulated according to different thickness of the EM wave absorbers using complex relative permittivity and permeability. The EM wave absorber was fabricated based on simulated data Simulated and measured values agree well. As a result, the developed EM wave absorber has a thickness of 3.38 mm and absorption ability over 20 dB at 5.8 GHz.

Development of the EM Wave Absorber for Preventing RFID Reader Interference in UHF band (UHF대역 RFID 리더 간섭방지용 전파흡수체 개발)

  • Park, Soo-Hoon;Choi, Chang-Mook;Song, Young-Man;Kim, Dong-Il;Jung, Ji-Won;Kim, Ki-Man
    • Journal of Navigation and Port Research
    • /
    • v.32 no.5
    • /
    • pp.349-353
    • /
    • 2008
  • In this paper, the EM wave absorber was designed and fabricated for preventing Reader Interference of RFID communication system in UHF band We fabricated several samples in different composition ratios of Amorphous and CPE(Chlorinated Polyethylene). Absorption abilities were simulated in accordance with different thicknesses of the prepared absorbers and changed complex relative permittivity and permeability due to composition ratio. The mixing ratio of Amorphous and CPE was searched as 80 : 20 wt.% by experiments and simulation. Then the EM wave absorber was fabricated and tested using the simulated data. As a result, the developed EM wave absorber has a thickness of 4 mm and absorption ability was over 20 dB in frequency range of $860\;MHz{\sim}960\;MHz$. Therefore, it was confirmed that the developed absorber can be used for suppressing RFID reader interference in UHF band.

Fabrication and Evaluation of the Super Thin-Type EM Wave Absorber for Suppressing EM Noises in 2.4 GHz Band (2.4 GHz 대역용 불요전자파 억제용 초박형 전파흡수체의 제작 및 평가)

  • Kim, Dong Il;Kwak, Hyun Soo;Joo, Yang Ick;Park, Soo Hoon
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.19 no.3
    • /
    • pp.500-506
    • /
    • 2015
  • In this paper, we designed and fabricated the EM wave absorber consisted of Sendust for suppressing EM wave noise PCB in ISM (Industrial, Scientific and Medical) band of 2.4 GHz. We fabricated several samples with different composition ratios of some kinds of Sendust to CPE (Chlorinated Ploy-ethylene) as a binder, and it was confirmed that the optimum composition ratio of absorbing materials was Flaked Sendust : CPE = 72.5 : 27.5 wt.%.. The absorbing abilities were simulated by changing the thickness and the measured material constants of EM wave absorber. The measured absorption abilities were analyzed and compared with the simulated ones. As a result, the simulated results agree well with the measured ones, and the developed EM wave absorber with extremely thin thickness of 0.6 mm has absorption ability of 5.4 dB at 2.4 GHz is excellent one. The thin type EM wave absorber can be applied for suppressing and absorbing electromagnetic noises from information and communication equipments.