• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.4
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• pp.397-405
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• 2004

In this paper, performance analysis of mobile phone with internal antenna for PCS band was carried out. The radiation patterns for antenna and mobile phone with internal antenna were simulated by using 3D simulation program, HFSS and SEMCAD. Radiation pattern variation was observed according to installation of LED circuit and ground pattern and by using simulation radiation pattern was improved. And radiation patterns of mobile phones with internal and external antennas were measured by using for field measurement system and chamber. Measured radiation pattern for mobile phone with internal antenna shows good agreement with simulation result. And the radio sensitivities of mobile phones with internal and external antennas were measured by using Agilent E5515C and chamber and compared. The measured radio sensitivity of mobile phone with internal antenna shows proper performances comparable to other model with external antenna. Measured result shows that the difference on averaged co-polar radio sensitivity is 0.12 ㏈.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.12
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• pp.1269-1275
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• 2003

In this paper, nonradiative dielectric(NRD) rotman lens with a gap-coupled unidirectional dielectric radiator(UDR) has been designed. Gap-coupled UDR is structurally suitable for NRD rotman lens. We have optimized NRD rotman lens for minimizing side-lobe, and calculated design parameters of UDR such as length of resonator and distance of gap using an equivalent circuit model of an evanescent NRD guide. Experimental prototype of UDR is fabricated and measured at the center frequency of 38 GHz. The simulated S-parameter and far-field radiation beam pattern of UDR show good agreements with measured data. Finally, total beam pattern of NRD rotman lens of multi-beam feed has been obtained using a measured pattern of UDR and array factor of NRD rotman lens. The obtained beam pattern shows remarkably suppressed side-lobe.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.2
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• pp.85-90
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• 1991

군사장비에 대한 EMI문제는 2차 세계대전 이후 전자장비에 대한 의존도가 높아짐에 따라 크게 변화하였다. 2차 세계대전 초기에는 주로 항공기의 엔진점화장치에서 발생되는 3~30MHz 대역의 무선주 파수간섭(RFI)이 통신장비에 문제가 되었으며 간섭현상도 그다지 심각하지 않았다. 그러나 전자공학의 급 속한 발전에 따라 고성능 통신장비 및 레이다가 등장하였으며 각종 전자장비도 고출력화, 고밀도화됨에 따 라 장비자체에서 방사되는 전자파잡음의 세기가 증가하게 되었다. 이에 반해 체계(System)탑재 전자장비 들이 점차 마이크로프로세서화 됨에 따라 제어신호의 수준은 더 낮아져서 전자파간섭에 더욱 취약하게 되 었다. 또한 현대의 전장(Battle Field)은 수많은 전기/전자장비가 동시에 운용됨에 따라 발생되는 전자파로 인해 더욱 복잡한 전자파환경이 형성된다.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.3
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• pp.10-14
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• 2017

A reverberation chamber is widely used in mobile handset measurements due to its faster and simpler measurement process compared to traditional anechoic chambers. We propose an ultra-wideband inverse conical antenna design suitable as a reference antenna in a reverberation chamber. Traditionally, multiple discone antennas are needed to cover more than 10:1 operation bandwidth of a reverberation chamber. The proposed inverse conical antenna offers wideband impedance matching bandwidth by virtue of the linear impedance transition along its oblique side. The antenna is feasible to mount on the conductive walls which can be utilized as a ground to improve the matching bandwidth, antenna gain and radiation patterns. The antenna geometry is optimized using a 3D electromagnetic simulation tool and fabricated using a 3D printer. The measured results show that the antenna reflection coefficient lower than -10dB and radiation efficiency more than 70% at the frequency range of 0.65~7 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1401-1411
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• 2010

In this paper, we suggested the tolerance limits of FAR(Fully Anechoic Room) using correlation factor between OATS(Open area Test Site) to measure EMI(Electromagnetic Interference) and FAR to measure EMS(Electromagnetic Susceptibility). FAR Project(SMT4-CT96-2133), CISPR/A/665/DTR, and CISPR A/665/DTR documents are analyzed and theoretical correlation factor based on the documents and theoretical equations is drawn. To obtain the experimental correlation factor, EUT(Equipment Under Test) is fabricated as well as measured at the 10 m distance OATS and in the 3 m distance FAR. Also, to suggest the tolerance limits of EUT with multi sources, radiation theory for electric and magnetic dipoles is programmed. We drew the correlation factor for EUT with multi sources through the programs. As the tolerance limits of FAR is newly defined, It can be used alternative test site for OATS to measure EMI, efficiently.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.409-414
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• 2005

This study is based on the recent CISPR(International Special Committee on Radio Interference) research which is focused on the Radiated Emission test method above 1 GHz and explained "w"(Measurements dimension) for the antenna's $\theta_{3dB}$ characteristic. And expound the work in progress in the IEC Standard for the measurement methods and the limits above 1 GHz.

• Electronics and Telecommunications Trends
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• v.6 no.4
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• pp.13-32
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• 1991

근래 정보화의 진전에 따라 전파이용분야의 수요가 높아지고 있으며 이러한 가운데 전파이용시설로부터 방사되는 전파가 인체에 나쁜 영향을 미치지 않을까 하는 불안과 의문이 제기되고 있다. 연구보고에 의하면 생체가 강한 전자파에 노출되는 경우 눈의 백내장 형성, 성기능 장해, 열적 손상, 경련, 행동 둔화 등의 생체작용이 일어나는 것으로 밝혀지고 있다. 그러나 무선통신시설을 비롯한 각종 전파이용시설로부터 방사되는 전파로 일상생활 범위에 있어서 염려하는 바와 같은 생체작용이 일어나는 일은 거의 없을 것으로 생각된다. 그러나 전파이용시설로부터 인체를 안전하게 보호하고 전파이용에 대한 공연한 오해와 불안을 방지하기 위하여 전파의 에너지 양과 생체작용과의 관계를 정량적으로 확실히 하는 일이 중요하며 이에 근거하여 전파로부터 인체를 보호하기 위한 안전기준을 제시하는 것이 요구되고 있다. 현재 미국, 일본, 독일, 영국, 캐나다 등 세계 여러 나라에서 전자파의 안전기준을 제시하고 있으나 우리나라에서는 아직 이러한 기준이 마련되어 있지 않다. 다음은 1990년 일본 (전기통신기술심의회) 에서 발표한 "전파이용에 있어서의 인체보호지침"을 발췌.요약한 것이다.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.470-474
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• 2006

In the case of dryer tendency that select directly without being serviced with salesperson's opinion specially because it does Purchase with sufficient knowledge is package of goods being high and labeling for goods of consumers are indicated to very important element This development wishes to escape and use "Seramik heater" and apply electromagnetic waves cover skill to be Hair Drier that head of a family electromagnetic waves are happened in method and household electric appliance that can raise sexual intercourse of circle infrared rays and High efficiency quantity of heat and coincide in high efficiency and All function anger request in existent metal heat ray.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.264-267
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• 2000

본 논문에서는 이동국의 안테나로부터 방사되는 전파의 일부가 인체에 흡수되므로써 기지국에서 수신되는 E$_{b}$ N$_{t}$의 감소에 대해 조사하였고, 감소된 E$_{b}$ N$_{t}$를 기준으로 하여 전파의 인체 흡수가 DS/CDMA BPSK 시스템의 성능에 미치는 영향을 분석하였다. 분석 결과, 인체에서의 흡수가 30[%]에서 40[%]로 증가할 때 기지국에서의 E$_{b}$ N$_{t}$, 값이 약 0.5 [dB] 정도 감소함을 알 수 있으며, 40 [%]에서 50[%]로 중가할 때에는 약 0.6 [dB] 정도 감소함을 알 수 있었다. 또한 시뮬레이션을 통해 사용자 수가 15 명일 때 약 2.5 [dB]의 E$_{b}$ N$_{t}$ 값에서 음성 서비스가 가능하다는 것을 알 수 있었다. 그리고 이러한 E$_{b}$ N$_{t}$ 값을 만족시키려면, 흡수율이 10 [%] 증가 할 때마다 안테나 방사 전력을 약 20 [mW] 이상 증가시켜야 한다는 것도 알아내었다. 것도 알아내었다.

• Journal of Auto-vehicle Safety Association
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• v.10 no.1
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• pp.12-19
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• 2018

This paper deals with the broadband electromagnetic emission test of a hybrid electric vehicle. The hybrid electric vehicle's powertrain system consists of an internal combustion engine and an EV traction motor. Depending on the SOC of the traction battery, these modes change automatically in the running state. The Korea electromagnetic compatibility regulations of KMVSS and UN WP.29 stipulated the evaluation method of hybrid electric vehicles. This study analyzes and compares two test results: internal combustion and electric motor mode. Some problems of test conditions are described and an improved test method is proposed for measuring broadband emissions of a hybrid electric vehicle. As a result, we expect this paper to be used as a consideration for improvement when test specifications are revised in the future.