• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.213-217
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• 2001

본 논문에서는 CPW 구조를 이용하여 60 GHz 무선 시스템 응용을 위한 V-band용 하향 주파수 혼합기를 설계 및 제작하였다. 하향 주파수 혼합기의 설계 및 제작에 있어서 GaAs PHEMT(Pseudomorphic high electron mobility transistor)를 기반으로 하였으며, 회로설계를 위해 coplanar waveguide(CPW) 라이브러리를 구축하여 이용하였다. 제작된 하향 주파수 혼합기의 변환이득은 국부발진주파수(LO) 입력이 8 dBm일 때 -8.5 dB의 최대 변환이득 특성을 얻었으며 Pl dB는 -3.3 dBm을 얻었다. 제작된 회로의 칩 크기는 1.6$\times$l.6 $\textrm{mm}^2$ 이다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.2
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• pp.141-145
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• 1997

The long wave infrared which is ranged to 4～1, 000 ${\mu}{\textrm}{m}$ is a kind of electromagnetic wave, and the wave is being absorbed by higher plant easily. The absorbed wave in the plant promotes the metabolism of plant cell by way of resonance with the water molecules of plant cell. This experiment was carried out to determine the effect of long wave infrared radiation ceramic on growth of rice seedling, and to make the optimum mixture rate of ceramic powder when ceramics was mixed with bed soil at 4, 8, 12, 16％ levels for machine transplanting. The results of this study indicate that the growth of the seedling significantly higher in the treatment sites than that of control sites. However, there was no significant differences in dry matter weight between the treatment and control sites. At the 9.6％ mixing ratio, the highest growth of rice seedling was found.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.5
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• pp.65-70
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• 2015

Lightning is one of hazards affecting the rapid-transit railway system. There are two effects, which are direct lightning surge to electric car line and induced lightning surge. Protection methods for the direct lightning surge are studied with various occasions, however, study of induced lightning surge is insufficient in spite of a large or small effects. In this paper, it is analysed the way that serge voltage is induced to electric car line by lightning strikes. By modeling the propagation process and the coupling phenomenon of electromagnetic wave produced by lightning strikes, it is achieved to make integrative circuit model combined with existing electric car model. The study is conducted into three different waveform of electromagnetic wave produced by lightning; rectangular wave, double exponential distribution wave, triangle wave. It is also simulated that the inducing serge is coupled to electric car line in an arbitrary location. The simulation results in that, when rapidly changing rectangular wave is supplied, maximum power is induced to electric car line.

• Journal of the Korean Magnetics Society
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• v.20 no.4
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• pp.143-148
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• 2010

This study examined the effects of sheet thickness on electromagnetic wave absorption characteristics and internal microstructure in 92.6%Fe-6.5%Si-0.9%Cr (wt%) alloy flakes/polymer composite sheets available for quasi-microwave band. The composite sheets with the thickness of 0.3, 0.4 and 0.5 mm were prepared by tape casting. A significant decrease in transmission parameter $S_{21}$ and a large increase in power loss were observed for the thick composite sheet in the frequency range of 1~5 GHz. However the permeability properties were not affected by thickness variation, while the imaginary part of complex permittivity increased with the increase of sheet thickness at 1~5 GHz. The enhanced electromagnetic wave absorption characteristics in the thicker composite sheets was attributed to the changed microstructure and the higher dielectric loss.

• Journal of IKEEE
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• v.22 no.3
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• pp.854-857
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• 2018

It becomes important to analyze the effects of electromagnetic wave on human body, as various wireless equipments are widely used in daily life. SAR (specific absorption rate) is a parameter of the effects of electromagnetic wave on human body. However, it considers only human tissues, and it is difficult to evaluate the effects of electromagnetic wave when metal artifacts are inserted such as dental implants. This paper introduces a method to simulate SAR, and gets its simulated results. Simulated SAR of human head model with dental implants in 30 GHz 5th generation mobile communications (5G) frequency band is $2.50{\times}10^{-3}W/kg$ in maximum and $8.58{\times}10^{-7}W/kg$ in average. These values are absolutely below 1.6 W/kg Korean domestic SAR limit.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.500-504
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• 2009

NiCuZn Ferrites, known as preventing EMI/EMC, were prepared and their properties were investigated based on the chemical composition ratio, sintering temperature, and mean particle size. The NiCuZn ferrite made of $Fe_2O_3$ 49.0 mol%, NiO 9.0 mol%, CuO 8.0 mol%, ZnO 34.0 mol% could be applied at the largest range of electromagnetic wave. The optimal calcination and sintering temperature were $900^{\circ}C$ and $1080^{\circ}C$, respectively. The electromagnetic wave loss capacity of its mean particle size $1.12{\mu}m$ was superior to others examined.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.22-27
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• 2016

The use of electromagnetic wave has been interested in various energy industry because it enhances a flame stability and provides higher safety environments. However it might increase the pollutant emissions such as NOx and soot, and have harmful influence on human and environments. Therefore, it is very important to understand interaction mechanism between flame and electromagnetic wave from environmental point of view. In this study, an experiment was performed with jet diffusion flames induced by electromagnetic wave. Microwave was used as representative electromagnetic wave and a flickering flame was introduced to simulate the more similar combustion condition to industry. The results show that the induced microwave enhances the flame stability and blowout limit. The unstable lifted flickering flames under low fuel/oxidizer velocity is changed to stable attached flames or lift-off flames when microwave applied to the flames, which results from the abundance of radical pool. However, NOx emission was increased monotonically with increasing the microwave power as microwave power increased up to 1.0 kW. The effects might be attributed to the heating of combustion field and thermal NOx mechanism will be prevailed. Soot particle was examined at the post flame region by TEM grid. The morphology of soot particle sampled in the microwave induced flames was similar to the incipient soot that is not agglomerated and contain a lots of liquid phase hydrocarbon such as PAH, which soot particle formed near reaction zone is oxidized on the extended yellow flame region and hence only unburned young particles are emitted on the post flame region.

• Journal of the Korea Institute of Building Construction
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• v.19 no.3
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• pp.209-217
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• 2019

EMP (Electromagnetic Pulse) usually means High Power Electromagnetic Wave (HPEM). In the case of the shielding plate against the EMP, there is a possibility of deterioration of the electromagnetic wave shielding performance due to the skill of the constructor, bad construction, deformation of the shielding plate at the connection portion (joint portion). The inefficient use of space due to the separation distance is also pointed out as a problem. Therefore, this study aims to derive the optimum electromagnetic shielding condition by applying ATMSM to concrete as a part of securing electromagnetic wave shielding performance with reflection loss against concrete wall. Experimental parameters included concrete wall thickness and application of Zn-Al ATMSM. For the concrete wall, the wall thickness was 100 to 300mm, which is generally applied, and experimental parameters were set for the application of Zn-Al metal spraying method to evaluate electromagnetic shielding performance. Experimental results showed that as the thickness increases, the electromagnetic shielding performance increases due to the increase of absorption loss. In addition, after the application of Zn-Al ATMSM, the average shielding performance increased by 56.68 dB on average, which is considered to be increased by the reflection loss of the ATMSM. In addition, it is considered that the shielding performance will be better than that when the conductive mixed material and the ATMSM are simultaneously applied.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.6
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• pp.427-437
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• 2019

In January, 2019, the Ministry of Science and ICT announced the third edition of Master Plans for Radio Wave Promotion, effective from 2019 to 2023. The focus of this plan is to implement market based radio wave policy and horizontal regulatory framework. Although it appears to be past due, such change in the radio wave policy is not only fair and structured, but also unprecedented and ground breaking in legality. In order to successfully implement market based radio wave policy and horizontal regulatory framework, we must implement identical radio wave license based on license with consideration and time-limited usage. Through this, efficient distribution of finite radio wave resource may come to reality. Furthermore, there must be an effort to include life style regulation on license into radio wave act in the future.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.275-282
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• 2012

This paper presents a comparison of antenna factor characteristics computed by the Method of Moments(MoM) and the electromotive force(EMF) method for a calculable dipole antenna with a hybrid balun. An expression for the antenna factor is formulated using the concept of power mismatch loss. The input impedance and effective length of the antenna, which are in the formula of the antenna factor, are calculated using the two methods. The results show that the antenna factors are agreed within 0.24 dB, although the maximum difference between the input impedances obtained from the two methods is about 17 ${\Omega}$.