• Title/Summary/Keyword: 전자파 차폐 효율

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An Experimental Study on the Development of Electromagnetic Shielding Concrete Wall for Shielding High-altitude Electromagnetic Pulse (HEMP) (고고도 전자기파(HEMP)차폐를 위한 전자파 차폐 콘크리트 벽체 개발에 관한 실험적 연구)

  • Choi, Hyun-Jun;Kim, Hyung-Chul;Lim, Sang-Woo;Lee, Han-Seung
    • Journal of the Korea Concrete Institute
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    • v.29 no.2
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    • pp.169-177
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    • 2017
  • Rather than causing damage from heat, blast, and radiation of a regular nuclear weapon, recently, it is predicted that North Korea has been inventing high altitude electromagnetic pulse (HEMP) missile in order to incapacitate electronic equipment. HEMP shielding facility is used for military purpose today. Despite the electromagnetic shielding effects from high quality compression plates, problems may include such as the possibility of electromagnetic influx resulting in the welding of the compression plates, and difficulties and high cost of construction. Therefore, in this study, a high electrical conducting material was added to the concrete experimental subject to ensure the shielding effect through electromagnetic waves to for the concrete structure, instead of building a shielding facility separately for the structure. Also, among the experimental subjects, 100 ${\mu}m$ of Iron-Aluminum alloy metal spraying coat was applied to two types with the highest shielding effect, and to two types with the lowest shielding effect. The result of the experiment indicates that experimental subjects added with a high electrical conductivity material did not meet the minimum shielding criteria of MIL-STD-118-125-1 standard, but all the experimental material applied to the metal spraying coating satisfied the minimum shielding criteria. In conclusion, it is considered that 100 µm of Iron-Aluminum alloy metal spraying coat contains high efficiency in the HEMP shielding.

Electromagnetic Shielding Characteristics of Polyaniline and Its Mixtures (폴리아닐린과 그 혼합물의 전자기파 차폐특성)

  • 박종수;임인호;최병수
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.2
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    • pp.293-298
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    • 2001
  • EB-NMP free standing film is manufactured from NMP solution of polyaniline(emeraldine base EB). Also ES(emeraldine salt EB . HCl) film is manufactured by doping of EB-NMP film with 1 mole HCI aqueous solution. And EB-mixture films containing conductor(carbon black, graphite, Ag etc.) are prepared, In this study, electromagnetic interference shielding efficiency(EMI SE) of ES free standing film ($\sigma$=5 S/cm, t=0.14mm) is 23~25 dB in the frequency range of 10 MHz~1 GHz. ES-mixture(carbon black, graphite, Ag etc.) films, polyaniline film doped camphorsulfonic acid(CSA) show higher EMI SE(30~34 dB, 36~42 dB, 44~52 dB, 34~43 dB) property than that of ES free standing film, respectively.

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Electrical Properties and Electromagnetic Shielding Effectiveness of Milled Carbon Fiber/Nylon Composites (분쇄형 탄소 섬유/나일론 복합재료의 전기적 성질과 전자파 차폐 효율)

  • 김창제;최형도;서광석;윤호규
    • Polymer(Korea)
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    • v.27 no.3
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    • pp.201-209
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    • 2003
  • DC and AC electrical conductivity and electromagnetic interference shielding effectiveness of milled carbon fiber/nylon composites were investigated with the kind of nylon matrix. Percolation transition at which the conductivity is sharply increased was observed at about 7 vol% of milled carbon fiber. Nylon 46 as a matrix was more effective to obtain high electrical conductivity than nylon 6, and the difference in conductivity was occurred by the treatment of coupling agent. Frequency dependence of AC conductivity could be explained by relaxation phenomenon at just below percolation and resonance phenomenon at 40 vol% of carbon fiber, respectively. Negative temperature coefficient phenomenon was found in all composites. Electromagnetic interference shielding effectiveness was increased with the concentration of carbon fiber. At a high conductivity region the return loss was more dominant to the total shielding effectiveness than the absorption loss.

A Study on the Evaluation Method of Shielding Effectiveness using NFS in Near-Field Tests (근거리장에서 NFS를 사용한 차폐효율 평가방법에 관한 연구)

  • Park, Jungyeol;Song, Inchae;Kim, Boo-Gyoun;Kim, Eun-Ha
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.8
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    • pp.76-82
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    • 2016
  • In this paper, we evaluated shielding effectiveness (SE) of carbon nanotube (CNT) film using near field scanning (NFS) in near field analysis. We adopted CNT film with deposit carbon density of 5% and thickness of 1mm for evaluation of shielding characteristic. Using a test coupon analogized to an actual IC package, we measured SE according to measuring position and SE according to distances between the CNT film and the test coupon. As a result, the measured SE in the near field varied with frequency. Especially, the measured electric field SE in the center of the test coupon is better than that of the measured edge point of the test coupon where it is affected by fringing effect. The results show that the measured SE in the near field is affected not only by frequency but also by measurement environment such as position and height of the probe and height of shielding film. In conclusion, we should choose proper methods for SE measurement considering interference distance in the electronic control system because there is little correlation between the proposed evaluation method in the near field and ASTM D 4935-10.

Perforated Plates Design Effective Shielding (효율적 전자파 차폐를 위한 개구면 설계)

  • 양승인;명노훈
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.2 no.3
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    • pp.60-66
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    • 1991
  • In this paper, circula and rectangular apertures arranged with triangular and rectangular lattices and having a certain thickness are considered for eddective electromagnctic wave shielding when the plane wave is incident normally to the perfectly conductingmaterrial. The shielding effectiveness is represented by the transmitted power which can be obtained by reflection and transmission coefficients using Floquet mode representation.

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Electromagnetic Interference Shielding Behaviors of Electroless Nickel-loaded Carbon Fibers-reinforced Epoxy Matrix Composites (무전해 니켈도금된 탄소섬유강화 에폭시기지 복합재료의 전자파 차폐특성)

  • Hong, Myung-Sun;Bae, Kyong-Min;Lee, Hae-Seong;Park, Soo-Jin;An, Kay-Hyeok;Kang, Shin-Jae;Kim, Byung-Joo
    • Applied Chemistry for Engineering
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    • v.22 no.6
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    • pp.672-678
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    • 2011
  • In this work, carbon fibers were electrolessly Ni-plated in order to investigate the effect of metal plating on the electromagnetic shielding effectiveness (EMI-SE) of Ni-coated carbon fibers-reinforced epoxy matrix composites. The surfaces of carbon fibers were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Electric resistance of the composites was tested using a 4-point-probe electric resistivity tester. The EMI-SE of the composites was evaluated by means of the reflection and adsorption methods. From the results, it was found that the EMI-SE of the composites enhanced with increasing Ni plating time and content. In high frequency region, the EMI-SE didn't show further increasing with high Ni content (Ni-CF 10 min) compared to the Ni-CF 5 min sample. In conclusion, Ni content on the carbon fibers can be a key factor to determine the EMI-SE of the composites, but there can be an optimized metal content at a specific electromagnetic frequency region in this system.

Study on Structural Changes and Electromagnetic Interference Shielding Properties of Ti-based MXene Materials by Heat Treatment (열처리에 의한 Ti 기반 MXene 소재의 구조 변화와 전자파 간섭 차폐 특성에 관한 연구)

  • Han Xue;Ji Soo Kyoung;Yun Sung Woo
    • Journal of the Microelectronics and Packaging Society
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    • v.30 no.3
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    • pp.111-118
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    • 2023
  • MXene, a two-dimensional transition metal carbide or nitride, has recently attracted much attention as a lightweight and flexible electromagnetic shielding material due to its high electrical conductivity, good mechanical strength and thermal stability. In particular, the Ti-based MXene, Ti3C2Tx and Ti2CTx are reported to have the best electrical conductivity and electromagnetic shielding properties in the vast MXene family. Therefore, in this study, Ti3C2Tx and Ti2CTx films were prepared by vacuum filtration using Ti3C2Tx and Ti2CTx dispersions synthesized by interlayer metal etching and centrifugation of Ti3AlC2 and Ti2AlC. The electrical conductivity and electromagnetic shielding efficiency of the films were measured after heat treatment at high temperature. Then, X-ray diffraction and photoelectron spectroscopy were performed to analyze the structural changes of Ti3C2Tx and Ti2CTx films after heat treatment and their effects on electromagnetic shielding. Based on the results of this study, we propose an optimal structure for an ultra-thin, lightweight, and high performance MXene-based electromagnetic shielding film for future applications in small and wearable electronics.

EMP Shielding Effectiveness of Water Pipe Structure Considering Attenuation Characteristics of Water (물의 감쇠특성을 고려한 배수관 구조의 EMP 차폐 효과 분석)

  • Kim, Woobin;Kim, Sangin;Kim, Waedeuk;Yook, Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.12
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    • pp.1011-1014
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    • 2017
  • Additional metal shielding is installed in the water pipes used in septic tanks to protect against damage from electromagnetic pulse (EMP) events. This shielding prevents EMP damage, but impurities present in water cannot pass through the shielding structure. Thus, the original function of the water pipes is lost as the pipes are blocked, and an additional maintenance workforce is needed to manage this blockage. To solve this problem, we propose a water pipe without an additional shielding structure; the proposed pipe was designed with consideration of the attenuation characteristics of water. The immersed depth was varied from 400 mm to 800 mm, while the diameter of the pipe was fixed at 100 mm. The shielding effectiveness increased from 70 dB to 100 dB around 2 GHz. Through the verification process, we propose an effective design guideline that can maintain the function of the water pipe and provide protection from EMP damages without additional shielding structure.

A Study on Adhesion of Mechanical Properties of Rubber by MgCl2 (투명 차폐 필름 구현을 위한 전도성 복합 바인더의 입자구조에 따른 성능 평가)

  • Park, Ji-won;Back, Jong-Ho;Lee, Tae-Hyung;Kim, Hyun-Joong
    • Journal of Adhesion and Interface
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    • v.18 no.2
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    • pp.59-67
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    • 2017
  • Recently, integration of parts is accelerating according to the growth of the smart mobile industry. The integration of these parts causes problems of interference phenomena between the parts, and the importance of electromagnetic wave shielding technology to solve this problem is highlighted. Electromagnetic wave shielding technology is implemented so as to reflect or absorb electromagnetic waves, and generally conductive materials are utilized for electromagnetic wave shielding. Transparent shielding technology is required according to recent industrial changes. In this research, we propose transparent the shielding film using imprint technology with conductive composite binder. Utilizing UV polymerized acrylic binder to produce a conductive composite binder. Spherical, plate and stacked silver particles were used for conductivity. The changes of the curing characteristics, conductivity and adhesion were observed according to the structural characteristics of the silver particles. The use of spherical particles was the most efficient in the curing process, and an additional curing system was required to complement the UV-shadowing structure. In the conductivity evaluation, the stacked structure showed excellent characteristics. The adhesion of spherical system was the best. It is evaluated as a result of irregularities on the surface. Ultimately, the patterned film using this showed excellent transparency characteristics.

Effect of Oxyfluorination on Electroless Ni Deposition of Carbon Nanotubes (CNTs) and Their EMI Shielding Properties (탄소나노튜브의 무전해 니켈도금 및 전자파 차폐 특성에 미치는 함산소불소화의 영향)

  • Choi, Ye Ji;Lee, Kyeong Min;Yun, Kug Jin;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.30 no.2
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    • pp.212-218
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    • 2019
  • To investigate the effect of the oxyfluorination of carbon nanotubes (OF-CNTs) on electroless Ni deposition and electromagnetic interference shielding efficiency (EMI SE), CNTs were treated with a mixture of oxygen and fluorine gases and sequentially deposited with nickel. These samples were then manufactured into thin films on a polyimide film to evaluate their EMI SE. The surface chemical property of OF-CNTs was investigated by X-ray photoelectron spectroscopy. From the results of thermogravimetric and scanning electron microscopic analyses, it was found that both the amount of deposited Ni and the surface morphology changed depending on oxyfluorination. Moreover, the Ni-deposited CNTs pretreated with $O_2:F_2=1:9vol%$ exhibited the maximum EMI SE as approximately 19.4 dB at 1 GHz. These results were attributed to the formation of oxygen and fluorine functional groups on the surface of CNTs due to the oxyfluorination, and the functional groups enabled to deposit a suitable amount of Ni and improve the dispersion in the deposited solution.