• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.4
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• pp.28-36
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• 1995

The use of image planes can reduce effectively the radiated emissions from a printed circuit board. This work deals with the influence of image planes on radiation from current trace. The configu- rations of one and two layers of image planes on both sides of current trace are proposed. The radiated emissions of those configurations have been calculated by solving a set of electric field integral equations by the method of moments. The induced current distributions on image planes and the radiation patterns are analyzed for different configurations of image planes, the distance between current trace and image planes, and the frequency of signal current.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.174-177
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• 2005

Offline switching power supplies have high voltage and high current switching waveforms that generate Electromagnetic Interference(EMI) in the form of both conducted and radiated emissions. Consequently, all off-line power supplies must be designed to attenuate or suppress EMI emissions below commonly acceptable limits. Electrodeless fluorescent lamp's ballasts have AC/DC flyback converter, so we must control the EMI emissions.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.217-221
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• 2006

Offline switching Power supplies have high voltage and high current switching waveforms that generate Electromagnetic Interference(EMI) in the form of both conducted and radiated emissions. Consequently, all off-line power supplies must be designed to attenuate or suppress EMI emissions below commonly acceptable limits. Electrodeless fluorescent lamp's ballasts have AC/DC flyback converter, so we must control the EMI emissions.

• 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.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.173-181
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• 2007

Radiated emission / susceptibility performance of the KSLV-I 2nd stage which are controlled from the unit level to the system level should be examined and managed all over the frequency ranges in order to ensure the normal operation of the SC, the 1st stage of the KSLV-I, ground support equipments which are installed at the space center, and other wireless communication networks. Not only unintentional electric field emissions from the KSLV-I system and its subsystems should be restricted to the levels less than the limits specified in the EMC requirements, but also proper test and evaluation method should be established, respectively. In this paper, radiated emission/susceptibility test limits, method, and test results of the KSLV-I 2nd stage engineering model are presented.

• ETRI Journal
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• v.17 no.3
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• pp.45-63
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• 1995

This paper proposes an algorithm to improve the correlation between giga-hertz transverse electromagnetic (GTEM) cell and open area test site (OATS). It is based on the dipole modeling process of an unknown source object in a GTEM cell and on the evaluation of the approximate far field equations correlated with measured GTEM powers at output port of the GTEM cell. In this algorithm, the relative phase differences between dipole moments play an important part in modeling the test object as a set of dipoles and offer stable calculation of emission values. The radiated emission test using this algorithm requires fifteen orientations of equipment under test, but the increased orientations as compared with the previous method have little effect on the time needed for testing. Radiation from a notebook computer has been tested for statistical analysis of the correlation between GTEM data and OATS data. The emission test results of the notebook computer show that the mean, the standard deviation, and the correlation coefficient are -0.62, 1.99, and +0.85, respectively. These figures indicate that this algorithm provides improved accuracy in the measurement of electromagnetic emissions over the previous method.

• Journal of electromagnetic engineering and science
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• v.11 no.4
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• pp.304-310
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• 2011

The application of time-domain methods in emission measurement instruments allows for a reduction in scan time by several orders of magnitude and for new evaluation methods to be realized such as the real-time spectrogram to characterize transient emissions. In this paper two novel systems for time-domain EMI measurements above 1 GHz are presented. The first system combines ultra-fast analog-to-digital-conversion and real-time digital signal processing on a field-programmable-gate-array (FPGA) with ultra-broadband multi-stage down-conversion to enable measurements in the range from 10 Hz to 26 GHz with high sensitivity and full-compliance with the requirements of CISPR 16-1-1. The required IF bandwidths were added to allow for measurements according to MIL-461F and DO-160F. The second system realizes a system of time-interleaved analog-to-digital converters (ADCs) and has an upper bandwidth limit of 4 GHz. With the implementation of an automatic mismatch calibration, the system fulfills CISPR 16-1-1 dynamic range requirements. Measurements of the radiated emissions of electronic consumer devices and household appliances like the non-stationary emissions of a microwave oven are presented. A measurement of a personal computer's conducted emissions on a power supply line according to DO-160F is given.

• The Korea Journal of Herbology
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• v.22 no.3
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• pp.39-45
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• 2007

Objectives : The purpose of this study is to investigate the delayed luminescence-biophoton emission from root of Angelica sinensis D., Angelica acutiloba K., and Angelica pubescens M. These three species of Genus Angelica are now imported from other nations into Republic of Korea. Methods : Randomly selected samples from roots of Angelica sinensis D., Angelica acutiloba K., and Angelica pubescens M. were radiated with 150 W metal halide lamp for 1 minute. After radiation. biophoton emissions of each sample were detected by electron multiplication(EM)-charge coupled device camera. The detected biophoton image was calculated with unit of counts per pixel. Results: The average biophoton emissions of delayed luminescence with EM ratio of $\times$150 and $\times$250 were distinguished significantly. The maximum biophoton emissions of delayed luminescence with EM ratio of $\times$250 were distinguished significantly. Conclusions : These results suggest that biophoton imaging of roots of Angelica sinensis D., Angelica acutiloba K., and Angelica pubescens M. could become the meaningful method for the study of differentiation for these three species of Genus Angelica.

• The Korea Journal of Herbology
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• v.21 no.2
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• pp.175-180
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• 2006

Objectives : The difference of delayed luminescence-biophoton emission was investigated in Cervi Pantotrichum Cornu selected randomly. Cervi Pantotrichum Cornu was used as a tonic in Korean medicine. Methods : Randomly selected samples of Cervi Pantotrichum Cornu were radiated with 150 W metal halide lamp for 1 minute. After radiation, biophoton emissions of each sample were detected by electron multiplication(EM)-charge coupled device camera. The detected biophoton image was calculated with unit of counts per pixel. Results : The average biophoton emissions of delayed luminescence with EM ratio of ${\times}l50\;and\;{\times}250$ were distinguished significantly. The maximum biophoton emissions of delayed luminescence with EM ratio of ${\times}250$ were distinguished significantly. Conclusion : These results suggest that biophoton imaging of Cervi Pantotrichum Cornu could become the meaningful method for the study of differentiation and classification of Cervi Pantotrichum Cornu.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.639-643
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• 2018

As electronic systems become smaller and more portable, the need for power conversion continues to increase. In addition, system stability must be ensured from switching noise due to power conversion efficiency and power conversion system miniaturization. Therefore, countermeasures to reduce switching noise during power conversion are essential. In this paper, a DC/DC buck converter circuit is constructed, and the characteristics of switching noise generated when changing the parts layout in a four-layer printed circuit board (PCB) structure with a reference plane are compared and analyzed. In addition, switching noise characteristics were compared and analyzed through simulations when the parts layout was different in a two-layer PCB structure from which the reference planes were removed. As a result, it was confirmed that the radiated emissions characteristic is reduced by 12dB and the conducted emissions characteristic decreased by 7dB to 8dB, according to the current return path in the four-layer PCB structure. Thus, it was confirmed that the noise characteristics can be improved according to the configuration of the current return path when the power conversion circuit is designed.