• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1950-1952
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• 2002

원자력 발전소 방사성 잡음 규제기준을 설정하기 위하여 발전소 내의 전자파 잡음 환경을 측정하였다. 대상 발전소는 1000 MW급 울진 원자력발전소 3호기로 발전소 출력 0 %에서부터 100 %까지 10일간 주 제어실 및 전기설비실 주변을 대상으로 US NRC Reg. Guide 1.180 및 Mil-Std-462D를 측정기준으로 하여 전기장 10 kHz ${\sim}$ 7 GHz. 자기장 30 Hz ${\sim}$ 100 kHz의 방사성 잡음을 측정하였다. 측정결과를 최소자승법을 이용한 회귀분석으로 잡음 한계값을 유도하여 미국 EPRI 및 NRC 측정결과와 비교한 결과 자기장의 경우 낮은 한계값을 보였고 전기장의 경우는 20 dB 이상 높게 결정되었다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.393-395
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• 2003

현장에서 많이 사용되고 있는 GIS에 결함이 발생하면 치명적인 사고로 진전될 수가 있다. 본 논문은 모의 GIS내 도전성 금속이물질 존재 시 발생되는 부분방전 신호를 절연 진단 방법중 하나인 UHF법을 이용하여 부분방전 시 방사되는 방사전자파의 스펙트럼을 분석해 금속이물질이 SF$_{6}$ 가스부분방전에 미치는 영향을 측정하였다. 이러한 연구는 현장 GIS 및 SF$_{6}$ 가스절연 전력설비에서 금속이물질에 의해 발생되는 절연파괴 사고의 방지에 중요한 역할을 할 것으로 사료된다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.330-333
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• 2006

산업현장에서 많이 사용되고 있는 전력기기에 결함이 발생하면 치명적인 사고로 진전되어 큰 경제적, 인적 손실을 가져온다. 본 논문은 GIS에 사용되는 절연가스인 $SF_6$의 압력 변화에 따른 부분방전을 모의하고, 발생되는 부분방전 신호를 절연 진단 방법 중 하나인 UHF법을 이용하여 부분방전 시 방사되는 방사전자파의 스펙트럼을 분석하고, 접지로 흐르는 방전 전류를 측정하여 방전진전 과정을 관측하였다. 본 연구는 GIS 및 $SF_6$ 가스를 절연물로 사용하는 전력설비에서 내부압력 변화 시 금속이 물질에 의해 발생되는 절연파괴 사고의 예방진단에 유용한 자료가 되리라 판단된다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.9 s.100
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• pp.917-925
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• 2005

In this paper, the quad-band antenna for mobile handsets is proposed and developed. The operating frequency bands include GSM(880 MHz${\~}$960 MHz), GPS(1,575 MHz$\pm$10 MHz), DCS(1,710 MHz${\~}$l,880MHz), and PCS(1,850 MHz${\~}$l,990 MHz). The proposed antenna consists of a feed line, a shorting post, and a radiating element of the feed loop. The multi-band operation is achieved by using the fundamental and higher resonant modes of the radiating element. Based on analysis of the current distribution on the radiator, the resonant frequency of each mode can be adjusted by adding the different sizes of slots on the radiator. The radiator of the feed loop is designed to be symmetrical so that the energy is symmetrically distributed on the radiator, which results in omni-directional radiation pattern. The ground plane under the radiator is removed in order to improve the bandwidth. The measured impedance bandwidths are $10.1\%$ in GSM band(VSWR<2.5), $26.8\%$ in GPS band, and DCS/US-PCS bands(VSWR<2.5), respectively. The maximum gains on the H-plane of the fabricated antenna are measured about -0.37 dBi${\~}$2.55 dBi for all operating frequency bands.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.4
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• pp.73-79
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• 2002

In this paper, electromagnetic waves radiated from discharge at three-type electrodes(needle-plane, plane-plane and sphere-plane electrode) using AC power source in air are measured and the peculiar patterns of their spectra are reported. The radiated electromagnetic waves were measured in bandwidth of VHF(30-230[MHz]) using a biconical antenna and a spectrum analyzer. When the discharge onset voltage range, high electric field intensity is shown in frequency band of 45, 70, 80[MHz] in case of needle-plane electrode configuration and 40[MHz] in case of plane-plane and sphere-plane electrodes configuration. However, when the breakdown voltage range, the frequency spectrum distribution of radiated electromagnetic waves appear different in the whole frequency range according to the shapes of electrode.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.244-250
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• 2012

The compact dipole antenna elements and array structure is proposed. The array structure is designed for applicator in regional hyperthermia treatment to enhance the uniformity of the heat distribution which makes the treatment effective and prevents overheating. The compact dipole is designed with branched dipole and matching network to have small size and symmetric shape. The temperature simulation with specific absorption rate(SAR) and bio-heat equation is performed to have heat distribution. The applicator is designed, fabricated, and measured with multi-channel thermometer in 30 and 60 minutes. The simulation and measurement results showed agreement and the simulation in body circumstance has proper temperature result for hyperthermia therapy.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.1
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• pp.37-47
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• 1995

In this paper, the slot coupled stacked microstrip antenna, which has wide bandwidth characteristics because of the double tuning effects from the interactions between two patches and feeding slot and improves distortions of radiation patterns due to spurious radiation from feeder, is analyzed. For the analy- sis Green function in the spectrum domain and Galerkin method is applied with an accurate analysis mode for slot coupled feeding structure using the scattering analysis method. The basis functions are 3 EB modes for patches and 5 PWS modes for feeder. The slot coupled stacked microstrip antennas are designed and fabricated with the center frequency of 11.5 Ghz and 12.0 GHz. The experimental results show the wide bandwidth characteristics of 1.9 ~ 2.2 GHz and agree well with the simulation results which have 15~20% bandwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.8 s.99
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• pp.810-814
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• 2005

Input power for TEM cell apparatus due to SAR(Specific Absorption Rate) for culture blood cell is determined by the transmission and reflection measurement of blood into the TEM cell. Blood cell with skin cell are reference culture cells for the study of EM wave effect. Exposure RF power from exposure apparatus to culture cell should not only exact for SAR value, but also should be based on the theoretical theory. In this paper, insertion loss of 50 g blood was measured to know exposure power per gram for culture blood cell, and input power of TEM cell due to SAR 0.8, 1.6, 3, 4 mW/g using the measured data are delivered. This study is for applying to EM wave exposure apparatus to culture cell.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.159-168
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• 2012

In this paper, we designed the antipodal vivaldi antenna for IR-UWB systems application and evaluated IR-UWB antenna performance for the ultra wideband impulse signal transmission in the time- and frequency-domain. The designed antipodal vivaldi antenna was fabricated using FR-4 substrate which thickness 1.6 mm, dielectric constant ${\epsilon}_r=4.7$ and $tan{\delta}=0.002$. We measured the return loss, far filed radiation pattern at the anechoic chamber in the frequency-domain. We also performed the pulse fidelity analysis in the time-domain using nano-second impulse signal transmission and demonstrated the feasibility of ultra wideband signal stable transmission in the UWB band. The designed and fabricated antipodal vivaldi antenna could be emitting and receiving the IR-UWB signal while preserving low pulse distortion and good radiation pattern in time- and frequency-domain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1139-1146
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• 2000

In this paper, circular-polarized dipole antenna with a novel structure is designed, simulated and fabricated for PCS or IMT-2000 base station at an arbitrary test frequency(1.575 GHz). Its radiation pattern is analyzed by means of physical optics(PO). The designed antenna is made up of a horizontal and a vertical dipole elements at a height of λ/4 above an reflector. One of λ/4 length vertical dipole element is located at a height of λ/8 above an reflector. In this case, circularly polarized radiation pattern is obtained by making impedance difference due to adjusting the length of each element. The characteristic of antenna measured from this study is that return loss is 18.4 dB, -10 dB bandwidth is 360 MHz(22.8%), 2 dB axial ratio bandwidth is 30 MHz, -3 dB beamwidth is 76$^{\circ}$, 2 dB axial ratio beamwidth is 58$^{\circ}$, axial ratio is 1.7 dB at 1.575 GHz. Radiation pattern is in well agreement with the result of PO.