• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.27-31
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• 2010

In this paper, we developed an EM wave absorber having the absorption ability of more than 15 dB for port logistics RFID system by using AMP. Firstly, we fabricated EM wave absorber by using AMP and CPE(Chlorinated Polyethylene) with different composition ratios 80:20 wt.% and 85:15 wt.%. Secondly, we designed the optimum EM wave absorber using the calculated material constants obtained from measured input impedance of the samples. Therefore, EM wave absorber with absorption ability of 17.5 dB at 433 MHz when composition ratio of AMP:CPE=85:15 wt.% and thickness of 5.5 mm.

• Journal of electromagnetic engineering and science
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• v.4 no.2
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• pp.51-55
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• 2004

With the progress of the electronics industry and radio communication technology, certain problems, such as electromagnetic interference(EMI), have arisen due to the increased use of electromagnetic(EM) waves. International organizations such as CISPR, FCC, and ANSI have provided the standards for the EM wave environment and for the countermeasure of the electromagnetic compatibility(EMC). EM wave absorbers are used for constructing an anechoic chamber to test and measure EMI and electromagnetic susceptibility(EMS). In this paper, we have designed an one-body EM(electromagnetic) wave ferrite absorber, based on the equivalent material constants method for both normally and obliquely incident waves, whose absorption abilities are superior to that of the conventional ones. The fabricated absorber has a thickness of 27.68 mm and shows an absorption ability over 20 ㏈ in the frequency from 30 MHz to 6 ㎓.

• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.671-674
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• 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.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.14-14
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• 2009

High frequency electromagnetic(EM) waves are increasingly being applied in industries because of saturationat lower frequency bands as a result of huge demand. However, electromagneticinterference (EMI) has become a serious problem, and as a result, highfrequency EM absorbers are now being extensively studied. Also, recentdevelopments in absorber technology have focused on producing absorbers thatare thin, flexible, and strong. Hence, one-dimension ferrous nano-materials area potential research field, because of their interesting electronic andmagnetic properties. Commercially, EM wave absorbing products are made ofcomposites, which blend the insulating polymer with magnetic fillers. Inparticular, the shape of the magnetic fillers, such flaky, acicular, or fibrousmagnetic metal particles, rather than spherical, is essential for synthesizingthin and lightweight EM wave absorbers with higher permeability. High aspectratio materials exhibit a higher permeability value and therefore betterabsorption of the EM wave, because of electromagnetic anisotropy. Nanowires areusually fabricated by drawing, template synthesis, phase separation, selfassembly, and electrospinning with a thermal treatment and reduction process.Producing nanowires by the electrospinning method involves a conventionalsol-gel process that is simple, unique, and cost-effective. In thispresentation, Magnetic nanowire and dielectric materials coated magneticnanowire with a high aspect ratio were successfully synthesized by theelectrospinning process with heat treatment and reduction. In addition toestimating the EM wave absorption ability of the synthesized magnetic anddielectric materials coated magnetic nanowire with a network analyzer, weinvestigated the possibility of using these nanowires as high-frequency EM waveabsorbers. Furthermore, a wide variety of topics will be discussed such as thetransparent conducting nanowire and semiconducting nanowire/tube with theelectrospinning process.

• Journal of Navigation and Port Research
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• v.32 no.5
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• pp.349-353
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• 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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.1-5
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• 2006

In this paper, the EM wave absorber was designed and fabricated for the collision-avoidance radar as a basic sensor of ITS(Intelligence Transport System), because radar system has some problems including false image and system-to-system interference. We fabricated some samples in different composition ratio of Carbon and CPE, and defined that optimum composition ratio of Carbon and CPE was 20:80 wt%. The complex relative permittivity was calculated by the measured data. And absorption abilities were simulated according to different thickness of the EM wave absorbers using the complex relative permittivity. The EM wave absorber was manufactured based on the simulated design. Simulated and measured results agree very well. As a result, the developed EM wave absorber with the thickness of 2 mm has absorption ability over 20 dB in frequency range of $76{\sim}77$ GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.244-249
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• 2008

In this paper, we designed and fabricated the EM wave absorber consists of Sendust and Mn-Zn ferrite for suppressing EM wave noise from PCB in ISM(Industrial, Scientific and Medical) band of 2.4 GHz. We fabricated several samples in different ratios of Sendust to Mn-Zn ferrite with CPE(Chlorinated Ploy-ethylene) as binder and confirmed that optimum composition ratio of absorbing materials was Sendust. Mn-Zn ferrite : CPE=70:5:20 wt.%. The absorbing abilities were simulated according to different thickness of EM wave absorber as the function of material constants calculated by measured data. Measured absorption ability was analyzed and compared with simulated result. The simulated result agree well with the measured ones. As a result, the developed EM wave absorber with thickness of 0.85 mm has absorption ability of 5.4 dB at 2.4 GHz and over 3 dB in frequency rage of 1.4$\sim$4.1 GHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1505-1510
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• 2014

High-Pass (ETC ; Electronic Toll Collection) system is one of the basic elements, which adopts a wireless communication method using 5.8 GHz and can realize a part of ITS (Intelligent Traffic System). On the other hand, communication errors occur frequently in Hi-Pass system due to signal erros, multi-path reflection, and/or system-to-system interferences. To solve these problems, an EM (Electro-Magnetic) wave absorber can be used. To solve these Problems, we fabricated some samples in the different composition ratios of Carbon, Sendust, and CPE, and it was confirmed that the optimum composition ratio of Carbon : Sendust : CPE is 10 : 40 : 50 wt.%. The complex relative permittivity and complex relative permeability were derived by using the measured data. In addition, the optimum design parameters for the absorber were determined by simulation. Then the absorption abilities were calculated by changing the thickness of the EM wave absorbers. As a result, the optimum thickness of the developed EM wave absorber was 2.85 mm with absorption ability over 22.4 dB at 5.8 GHz. Futhermore, the EM wave absorber was fabricated based on the simulated and designed values. The measured values agreed well with the simulated ones. Therefore, it was clearly shown that the developed EM wave absorber in this paper is to be applied in actual situations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.500-506
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• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1040-1046
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• 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.