• Title, Summary, Keyword: Near-Field Electromagnetic Shielding

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A Study on the Electromagnetic shielding Effectiveness Using Conductive Polymers (전도성 고분자를 이용한 전자파 차폐효과의 연구)

  • 하남규;이보현;김태영;김종은;서광석
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.3
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    • pp.207-214
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    • 2001
  • The conductive polymers, polyaniline (PANI) emeralidin base and 3,4-polyethylene dioxythiophene(PEDOT) were synthesized and coated on the PET film dealt with acryl type primer to study the electromagnetic shielding effectiveness. When both PANI and PEDOT were coated on the PET film dealt with acryl type priemer, their surface properties such as he adhesive increased. For PANI, when blended with the binder such as PMMA, it adhesive and surface hardness increased, too. The visible light transmittance decreased, while the electromagnetic shielding effectiveness increased, when coated thickness of PANI and PEDOT increased. For PANI, the electromagnetic shielding effectiveness increased as its surface resistance decreased. For PANI, when the surface resistance was 140 Ω/$\square$, the shielding effectiveness was found to be 11 dB in the far field, and 13 dB in the near field at 1 GHz. For PEDOT, when the surface resistance was 200 Ω/$\square$, the shielding effectiveness was found to be 3 dB in the far field, and 7dB in the near field.

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The Electromagnetic Shielding Effectiveness Using Conducting Polymers (전도성 고분자를 이용한 전자파 차폐효과)

  • 하남규;김종은;서광석
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.306-309
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    • 2000
  • The conductive polymers, polyaniline (PANI) emeraldine base and 3, 4-polyethylene dioxythiophene (PEDOT) were synthesized and coated on the PET film primer-dealt with acryl type to find out the electromagnetic shielding effectiveness. When conductive polymer such as PANI and PEDOT is used, if the thickness of coating increases then the electromagnetic shielding effectiveness increases, too, but the visible light transmittance decreases. For PANI, when its conductivity increased, its electromagnetic shielding effectiveness increased, too. For PANI, if the surface resistance is about 140 $\Omega$/$\square$, the shielding effectiveness is about 11 dB in the far field, and about 13 dB in the near field at 1 GHz. For PEDOT, when the surface resistance is about 200 $\Omega$/$\square$, the shielding effectiveness is about 3 dB.

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Microfabrication of Microwave Transceivers for On-Chip Near-Field Electromagnetic Shielding Characterization of Electroplated Copper Layers (극소형 전자기파 송수신기의 제작 및 전기도금된 구리박막의 칩단위 근접 전자기장 차폐효과 분석)

  • Gang, Tae-Gu;Jo, Yeong-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.6
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    • pp.959-964
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    • 2001
  • An experimental investigation on the near-field electromagnetic loss of thin copper layers has been presented using microfabricated microwave transceivers for applications to multi-chip microsystems. Copper layers in the thickness range of 0.2$\mu$m∼200$\mu$m have been electroplated on the Pyrex glass substrates. Microwave transceivers have been fabricated using the 3.5mm$\times$3.5mm nickel microloop antennas, electroformed on the silicon substrates. Electromagnetic radiation loss of the copper layers placed between the microloop transceivers has been measured as 10dB∼40dB for the wave frequency range of 100MHz∼1GHz. The 0.2$\mu$m-thick copper layer provides a shield loss of 20dB at the frequencies higher than 300MHz, whereas showing a predominant decreases of shield loss to 10dB at lower frequencies. No substantial increase of the shield effectiveness has been found for the copper shield layers thicker that 2 $\mu$m.

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.

Analysis for Shielding Effectiveness of Metal Shielding Layer within Near-Field of Noise Source (노이즈 소스 근거리장에 위치한 금속 차폐막의 차폐효과 분석)

  • Lee, Won-Seon;Lee, Won-Hui;Hur, Jung
    • The Journal of The Institute of Internet, Broadcasting and Communication
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    • v.19 no.3
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    • pp.59-65
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    • 2019
  • The EMI shielding effectiveness of the shielding layer thickness was analyzed when the metal shielding layer was placed in the near field of the magnetic probe and the noise source. Microstrip lines were used as noise source, and graphite and ferrite were selected as metal shielding materials. The magnetic probe uses the electromagnetic radiation measurement method using the magnetic probe by applying the IEC 61967-6 method. The transmission coefficient between the microstrip line and the magnetic probe was analyzed. The distance between the two was 1 mm for a single shielding layer and 5 mm for a multiple shielding layer. The thickness of the shielding layer was changed to 5 um, 10 um, 30 um, and 50 um. When the frequency was changed from 150 kHz to 1 GHz, a maximum shielding effectiveness (SE) of 44.9 dB was obtained.

Electromagnetic wave Shielding Materials for the Wireless Power Transfer Module in Mobile Handset (휴대단말기 무선전력 전송모듈용 전자기파 차폐소재)

  • Bae, Seok;Choi, Don-Chul;Hyun, Soon-Young;Lee, Sang Won
    • Journal of the Korean Magnetics Society
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    • v.23 no.2
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    • pp.68-76
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    • 2013
  • Currently, wireless power transmission technology based on magnetic induction was employed in battery charger for smart phone application. The system consists of wireless power transmitter in base station and receiver in smart phone. Size and thickness of receiver was strictly limited in the newest smart phone. In order to achieve high efficiency of a tiny small wireless power receiver module, sub-millimeter thick electromagnetic wave shielding sheet having high permeability and Q was essential component. It was found that magnetic field from transmitter to receiver can be intensified by sufficient shielding cause to minimize leakage magnetic flux by those magnetic properties. This leads to high efficiency of wireless power transmission and protects crucial integrated circuit of main board from electromagnetic noise. The important soft magnetic materials were introduced and summarized for the current small-power wireless power charger and NFC application and mid-power home appliance and high-power automotive application in the near future.

Magnetic Shielding with Thin Magnetic Materials near Power Cables (박판 자성 재료를 이용한 전력 케이블 인근의 자기장 차폐)

  • Kim, Sang-Beom;Soh, Joon-Young;Shin, Koo-Yong;Jeong, Jin-Hye;Myung, Sung-Ho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.7
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    • pp.639-647
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    • 2009
  • In this work, wrapping conductors with thin magnetic materials is proposed as a magnetic shielding method. The 0.1 mm thick metal sheets of mu-metal, grain-oriented electrical steel, and non-oriented electrical steel were produced from commercial alloy sheets through cold rolling and followed high temperature annealing. In case of 3-phase electric currents, mu-metal was the best in shielding performance at a B-field magnitude of about 100 ${\mu}T$, whereas silicon steels were better than mu-metal at a B-magnitude over 500 ${\mu}T$. In addition, wrapping with silicon steel(inner) together with mu-metal(outer) resulted in a shielding factor less than 0.1 even at 500 ${\mu}T$. These results are due to changes in hierarchy of magnetic permeabilities of the materials with increasing magnetic field strength. In case of single-phase electric current, B-magnitude outside the magnetic shell was rather increased compared to the unshielded case. This result is explained by vector composition of B-fields near magnetic shielding materials.

An Analysis of FCCL Shielding Effect for EMF Attenuation to On-Line Electric Vehicle (On-Line Electric Vehicle의 EMF 저감을 위한 FCCL 차폐효과 분석)

  • Shim, Hyung-Wook;Kim, Jong-Woo;Cho, Dong-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.6
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    • pp.770-775
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    • 2014
  • According to ICNIRP guidelines for limiting exposure to time-varying electric, magnetic and electromagnetic fields up to 300GHz, magnetic flux density which range from 3Hz to 150kHz are regulated to lower than $6.25{\mu}T$. In order to comply with its standard, OLEV(On-Line Electric Vehicle) have been designed considering EMF(Electro-Magnetic Field) reduction. However, if a current flowing in power line would be bigger for increasing power transfer efficiency, the established shield system no longer acts their role properly. In this paper, therefore, FCCL(Flexible Copper Clad Laminate) is applied to power line and pick-up devices to solve the problems. Though, the FCCL is normally utilized to insulator on circuit board, because of its high heat resistance characteristic, flexibility and thin properties, it makes effectiveness in the shielding device as well. 4 types of FCCL shielding structure are introduced to power line and pick-up devices. From the results, the FCCL which are placed in proposed positions shows maximum EMF reduction compared to the established shielding structure. Henceforth, if OLEV is applied FCCL shielding structure in practice, it will not only be more safe but also step forward to commercialization near future.

Analysis of Penetration Phenomenon of High Altitude Electromagnetic Pulse into Buried Facilities with Various Moisture Content and Depth (수분 함유량 및 지하 구조물 깊이에 따른 고고도 전자기파(HEMP) 투과 현상 분석)

  • Kang, Hee-Do;Oh, Il-Young;Yook, Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.6
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    • pp.644-653
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    • 2013
  • In this paper, a formulation for obliquely incident electromagnetic wave has been presented for an analysis of highpower electromagnetic pulse penetration into multilayered dispersive media. Based on generalized models of measured dielectric constants and propagation channels reflecting the Earth's general features, the propagation phenomenon of the obliquely incident early-time(E1) high altitude electromagnetic pulse(HEMP) is analyzed. In addition, the polarization and critical angle are also considered. It is found that the total reflection occurs at an incident angle of about 38 degrees at the soil-rock interface, and that the parallel-polarized E1 HEMP penetrates better than the perpendicular-polarized one. The peak level of the penetrating electric field is found to be 5.6 kV/m at normal incidence, regardless of the type of polarization, and E1 HEMP is greatly reduced near the critical angle. Moreover, the penetrating E1 HEMP is analyzed as a variation of moisture content and depth of materials, resulting E1 HEMP could be useful in determining the levels of shielding required for buried facilities.