• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.432-436
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• 1999

The development of Electromagnetic Communication technology have made our life abundant. However, the countermeasure of EMI(Electromagnetic Interference) are more important socially as increase of a main cause on electromagnetic waves occurrence. It is required that the absorbing ability of an electromagnetic wave absorber is above 20 dB, the bandwidth of which is required from 30 MHz to 1,000 MHz for satisfying the international standard about EMI and also will be required from 30 MHz up to 5,000 MHz in the bandwidth. In this paper, we proposed the square projection type absorber satisfying the above requirements and carried out broadband design using the equivalent material constants method.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.143-147
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• 2014

The ECU which is operating inductive actuator like motor or solenoid should be designed with considering the heat removal performance and the EMC performance. In most cases, these two performances are trade-off. Especially, the metal cover with plastic housing for improving heat removal performance can affect EMC performance by coupling the noise source to harness cable and connector. Therefore, after analyzing the EMC effectiveness of the metal cover, countermeasures for EMC noise reduction should be established. In this paper, by simulating and testing of AHB Gen3 ECU, the influence of the metal cover to EMC performance is analyzed. And based on this result, we propose solutions for EMC noise reduction.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.5
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• pp.1055-1063
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• 2013

CTL cell that is one of the standard electromagnetic generation equipment can measure the characteristic of the electromagnetic susceptibility and the electromagnetic interference. In case of being input the same magnitude signal with the phase difference of 0o or the phase difference of 180o at two input ports of CTL cell to be the fundamental resonant frequency(TE011) of 2.20GHz, the characteristics of the electric field and the magnetic field at the uniform area were measured. And, it measured the electric field characteristic due to the variation of the input power, the test position and the input frequency under the dominant E-field and the dominant H-field of CTL cell. Using these mesuremed data, it examined the operation characteristic and the available frequency band of CTL cell.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.1 s.104
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• pp.74-80
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• 2006

This paper presents the characteristics of electromagnetic field uniformity in a reverberation chamber that can be used alternatively for the analysis, test and evaluation of electromagnetic interference and immunity. The dual-band diffuser, which can be used at two different frequency bands in a reverberation chamber, is applied, and it is made of two different single-band Schroeder's Quadratic Residue Diffusers. The FDTD method is used to analyze the field characteristics. Compared with single-band diffuser, the dual-band diffuser shows the improvement in not only expansion of test frequency band but also in characteristics of the field uniformity, polarity, power efficiency, and tolerance. Therefore, the reverberation chamber with the dual-band diffuser is a better facility, for the analysis and measurement of electromagnetic interference and immunity, than the reverberation chamber with a single-band diffuser.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1184-1193
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• 2010

The upper frequency of international EMC regulations is being expanded above 1 GHz. Radiated emissions above 1 GHz are different from those below 1 GHz that is existing upper regulation frequency, and which have lower field strength and sharper and tilted beam-width, relatively. In this paper, an effective evaluation method to be used above 1 GHz is studied using an offset parabola antenna system having a double-ridged horn antenna as a feed. First, simple model is proposed for calculating antenna factor and field uniformity of the parabola antenna system, and then real radiated emission and radiated susceptibility measurements are performed using a constant noise emitter and the suggested antenna system. The results show that the proposed antenna system has higher gain and power efficiency, and wider field uniformity relative to a conventional double-ridged horn antenna. Therefore, it is confirmed that the proposed system can be effectively used for EMC measurements above 1 GHz.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.343-343
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• 2001

최근 전자산업과 전파통신산업의 발달에 따라 불요전자파에 의한 전자파장해가 심각한 수 준에 이르게 되었다. 그 결과 국 . 내외 전자파환경은 나날이 악화되고 있으며, 이로 인한 사 회적 문제가 점차 증가되고 있는 실정이다. 이에 대한 대책으로 CISPR(Comite Internationale S Special des Perturbations Radioelectrique), FCC (Federal Communications Commissions) A ANSI(Amercian National Standards Institute) 둥이 주축이 되어 국제 규정이 제정되어 각종 전자기기들에 대해 방사(EMI) 및 내성(EMS)의 규제가 강화되고 있다. 그러나 국제규정이 요구하는(30 MHz - 18 GHz) 주파수 범위에서의 EMIjEMS 측정을 하기 위해 광대역(Broad-band) 전파무향실(Anechoic Chamber)이 필요하지만1 기존의 Ferrite T Tile 또는 그리드형 전파홉수체는 20 dB 이상 전파를 홉수할 수 잇는 주파수 대역이 30 M MHz - 400 MHz 또는 780 MHz에 불과하기 때문에 상기의 조건을 만족하는 전파무향실 을 구성하기에는 곤란한 실정이다. 본 논문에서는 국제 규격을 만족하는 전파무향실을 위한 광대역 전파홉수체를 개발하기 위해, 다충형으로 구성하고, 전파흡수체의 형상을 변화시켜 등가재료정수법을 사용하여 설계하고 그 특성을 평가함을 그 목적으로 하였다. 따라서 본 논문에서는 본 연구실에서 기폰에 제안한바 있는, 금속판 위에 타일형 페라이 트 충, 그 위에 원추절단형 페라이트 층과 원통형 페라이트 층을 적층시칸 형상의 전파홉수 체는 30 MHz - 6 GHz 정도까지 커버할 수 있으나, 1 GHz 부근의 주파수 대에서 16 dB 정도의 홉수능 밖에 가지지 못하였다. 이를 개선하기 위해, 금속판 위에 타일형 페라이트 층 을 형성하고 그 위에 원통형 페라이트 충, 원추절단형 페라이트 충I 원통형 페라이트 충, 타 원형 페라이트 충을 형성한 새로운 형태의 전파홉수체를 제안하였다. 본 논문에 제안한 새로운 형태의 전파흡수체의 시물레이션 결과 30 MHz - 20 GHz의 주파수 범위에서 전반적으로 25 dB이상의 전파흡수능을 가짐을 확인하였으며/ 특히 기폰에 제안한 전파홉수체와 비교하면,1GHz 부끈에서의 전파홉수능을 10 dB 이상 개선하였다. 나아가서/ 실재로 제작한 전파흡수체의 측정된 주파수특성이 시율레이션에 의한 이론치와 3 30 MHz - 6 GHz의 범위에서 잘 일치함을 확인하였다. 또한y 전파 홉수체의 전체 높이는 2 27 mm 밖에 되지 않으므로 본 연구에서 제안한 전파 홉수체를 사용할 경우 전파무향실의 유 효공간 확보에 매우 유리한 이점을 가진다

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.5 s.120
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• pp.471-477
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• 2007

This paper presents the characteristics of electromagnetic field uniformity in a reverberation chamber with flat diffusers composed of multiple dielectric materials that can be used as an alternative facility for the analysis, test and evaluation of electromagnetic interference and immunity. The field characteristics and the size of the test volume inside the reverberation chamber with the new diffuser of multiple dielectric materials are simulated and analyzed at $2.5{\sim}3$ GHz band. The FDTD method is used to analyze the field characteristics. The field uniformity, polarization characteristics and tolerance are improved by the new diffuser with smaller physical size. The reverberation chamber with flat diffusers composed of multiple dielectric materials shows better electromagnetic performance and larger test volume than normal chamber.

• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.33-37
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• 2010

It is very important to prevent the electromagnetic interference and to prevent malfunction of electronic equipments mounted on ships. To solve these problems, in this paper, the EMC filter was designed, fabricated, and tested. The Ni-Zn ferrite beads with high permeability were used to make large inductance as the inductor and the feed-through capacitors without any resonance points. As a result, excellent attenuation characteristics of 25~70 dB were obtained from the 0 kHz~1.5 GHz band. In addition, when the Electric Fast Transient (EFT) of 4 kV in the level 4 of IEC 61000-4-4 was induced the EFT reduced to 600 V. Therefore, it was clearly shown that the developed EMC felter can be used for suppressing the electromagnetic interference on-board electronic devices and equipments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.6 s.97
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• pp.622-631
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• 2005

In this paper, we reduce 'over and under deviation' and 'over and under testing' which have a cause of uncertainty in electromagnetic radiated immunity test. We analyze continued measurement method of field uniformity and propose new estimate method having the minimum uncertainty condition. We test comparison in 4 anechoic chambers and analyze FDI(Field Deviation Index) which is the minimum deviation excess 6 dB on fields. We obtain that the proposed test method improve 1.193 dB than domestic standard(KN 61000-4-3) and 0.017 dB than international standard (IEC61000-4-3) in every frequency. In the test result 'over and under testing point' have 926 point at every field area and have 118 point at center uniform area. These result know that proposed measurement method have 10 point less at every field area and 9 point less at center uniform area than continued measurement method. The proposed test method have few point more than continued measurement method. Therefore, we confirmed that the proposed test method have the minimum uncertainty in electromagnetic radiated immunity test.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.291-298
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• 2016

In this paper, we studied about the radiated emission of EFT(Electrical Fast Transient)/Burst signal, referenced IEC-61000-4-4 of the international EMC standard and its effect on EUT(Equipment Under the Test) when EFT/Burst signal (Conducted noise) induced on a power cable to EUT. Firstly, we set up test sample by the standard and +4 kV standard signal is induced by EFT/Burst signal generator with 1 m length power cable for 1 minute. Consequently, we found not only induced EFT/Burst signal along power line, but also directly radiated emission signal from EFT/Burst signal generator (Radiated emission noise of EFT/Burst). The radiated emission signal of EFT/Burst was 30 dB which is higher than limit of CISPR 22 which is international EMC standard. Moreover, we measured the electric field strength by changing distance from maximum radiated emission point to electric field strength tester. As a result, this electric field strength was 23 V/m which is higher than international EMC standard test level(CISPR 24). Therefore, it was confirmed that the probability of malfunction may be high when radiated emission of EFT/Burst noise exists near the EUT.