• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.352-359
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• 2001

We propose the row method that is able to consider the SAR compliance test from the very beginning step of developing the mobile phone. The reason this new method is plausible is that we adopt the certified FDTD for the reliability of calculation, utilizing 1 mm high resolution model that is to model the phantom and the mobile phone almost identically to the reality. In this paper we introduce the process that will apply the proposed method in order to reduce the SAR of the mobile phone that has been problematic in satisfying the SAR compliance test. It results in dropping in the SAR that we keep the mobile phone or its antenna while we use it. Therefore here we make a claim as fellows. When we develop the new mobile phone, we should use the computer simulation combining the CAD design and radiation pattern rather than make a prototype and then use the trial and error method. Moreover the former way leads us to boost up the developing efficiency and reduce the cost.

• 프린팅코리아
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• v.7 no.6
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• pp.128-131
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• 2008

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.421-430
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• 2003

In this paper, we propose a method to consider SAR(Specific Absorption Rate) at beginning stage of handsets development. First, simulation was carried out with changing folding angle from 150$^{\circ}$to 142$^{\circ}$. Simulation results show that SAR value is decreased with decreasing the folding angle. When folding angle is 142$^{\circ}$, error between simulation and measurement results is about 3.95 %. Second, we made some experiments with EMI (Electromagnetic Interference) paint, and its results show that different pattern of EMI paint have different SAR values. After removing EMI paint at the lower part of antenna feeding point, we got the decrease efficiency of 15.46 % for SAR value. When we applied zigzag painting pattern, we got the highest SAR decrease efficiency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.2
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• pp.155-163
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• 2002

In this paper, we propose SAR reduction methods based on power conservation relation, After defining SRF(SAR Reduction Factor) for a more quantitative discussion of effective SAR reduction methods, many kinds of simulation have been performed. We compare the SAR by a flip type handset with that of folder type one. It is found that in a typical position of handsets over a human head, the SAR when using the folder type is about 30 % smaller than that when using the flip type. The effects of ferrite material when using flip type handset are shown to be not considerable when using a folder type.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.409-426
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• 2001

Absorbed power of the human head radiated from a 900 MHz portable phone and temperature rise are computed using FDTD(Finite-Difference Time-Domain) method. For this computation the 5 layered media for the human head modeling and the monopole antenna attached to metallic box for the portable phone are used. To reflect the real circumstances typical sizes of human heads and portable phones are considered in the calculation. The length of monopole antenna is 8.15 cm, and the output power of a phone is 600 mW. Under the predetermined model the distribution of 1 g, 10 g averaged SAR and temperature rise rate over the human head are calculated, from which it was found that the position of maximum SAR is near at the head skin surface, not deep places far into the head. The position of the highest temperature is located far from the head skin more than that of the maximum SAR occured. The averaged SAR and temperature along the distance between the head and phone are calculated according to seperation distance between the head and phone.

• The Magazine of the IEIE
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• v.28 no.2
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• pp.51-58
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• 2001

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.2
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• pp.277-290
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• 1999

A simulation using the finite-difference time-domain method to analyze the electromagnetic interactions between a cellular phone and the human body was conducted, and a synthesis of a bone-equivalent material to make a human head phantom was performed. A test model of the cellular phone was fabricated to measure its reflection coefficient and radiation pattern in the free space. Various effects of the human body on the characteristics of the phone, such as input impedance, reflection coefficient, radiation pattern, and radiation efficiency are analyzed as the distance between the head and the phone antenna varies. When the phone was operated close to the head, the resonant frequency of the antenna decreased by up to 12%. With the output power of 0.6W, as long as the distance was larger than 30mm, the 1-g averaged peak SAR was below the ANSI/IEEE safety guideline, 1.6 W/kg. To synthesize the bone-equivalent material, an epoxy with hardener and a graphite powder were used as basis ingredients, and a small amount of a conducting epoxy was added to control the conductivity of the material. A material having a relative permittivity of 18.04 and a conductivity of 0.347, which are close to those of the bone at 850 MHz, was synthesized.

• The Science & Technology
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• v.31 no.6 s.349
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• pp.84-85
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• 1998

의료용기구를 수입에만 의존하던 우리나라 의료업계는 IMF영향으로 큰 타격을 받고 있다. 이처럼 외환위기에 시달리는 때 연세대의대 김덕원 교수는 치아 신경치료에 필수적으로 사용되는 치아신경관 측정기를 개발해 각광을 받고 있다. 김교수는 또 휴대폰에서 나오는 전자파가 의료기기 작동에 미치는 영향이 크다는 사실을 확인하고 '휴대폰 유해'연구도 계속하고 있다.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.05a
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• pp.251-256
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• 1998

근래에 들어와 산업화가 급속히 진행되면서 공해문제가 심각하게 대두된 것과 마찬가지로 전자산업의 발달에 힘입어 전자공학을 응용한 여러 종류의 다양한 장비가 널리 보급됨에 따라 전자파 공해문제가 꾸준히 제기되었다. 이를 전자파 장해 (EMI : Electromagnetic Interference)라고 한다. 특히 컴퓨터 화면에서 전자파가 발생되어 사용자에게 심각한 영향을 준다는 VDT증후군, 전력선 주변의 주민들에게 발생된다는 백혈병, 휴대폰의 사용에 의하여 발생될 수 있다는 뇌암등, 인체에 해로운 효과가 발생된다는 검증된 또는 검증되지 않은 내용이 매스컴에 의하여 그대로 전달됨으로 인하여 전문적 지식이 부족한 일반인들에게 상당한 심리적 압박을 주어 왔다. (중략)

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.384-385
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• 2008

본 논문은 전력선이나 무선기지국 처에서 방축된 전자파를 인터넷, 휴대폰 등 통신수단을 이용하여 원격지에서 실시간으로 측정, 감시할 수 있도록 고안된 전자파 인체노출 원격측정 시스템에 대하여 기술한다. 본 시스템은 측정 자동화 및 무인차 개념이 도입되었으며, 국제규격에서 권고한 측정프로토콜에 따라 측정수행이 되므로 전자파인체노출기준의 적합성 여부론 판단하는 표준측정 시스템으로도 활용될 수 있다.