2000 Fiscal Year Final Research Report Summary
Research on seaching and reducing technique of electromagnetic interference for information systems installed in the building
| Project/Area Number |
11834013
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Institution | Kyushu Tokai University |
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Principal Investigator |
TDEGUCHI Tsuyoshi kyuusyu Tokai Unversity, School of Engineering, , Professor, 工学部, 教授 (60289626)
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| Co-Investigator(Kenkyū-buntansha) |
KOGA Hiroaki Kumamoto National College of Technology, Professor, 教授 (40249884)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Electromagnetic noise / Metallic conductor line / Balance-unbalance conversion factor / Electromagnetic wave radiation / Metallic evaporated sheet / Equivalent ground plane / Effective power |
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| Research Abstract |
Research on seaching and reducing technique of electromagnetic interference for information systems installed in the building were carried out, mainly by focusing the noise propagating mechnism on lines installed in buildings. And following results were obtained.
(1) Balance-unbalance conversion characteristics of effective poer on untwisted off-balanced metallic pair lines were investigated over a wide range of frequencies in the MHz region. First, we developed a method to estime effective power conversion factors using a cascade connection of F matrixes, where the imbalance in impedance and admittance of each pair line is distributed uniformly along the line. As a result, the frequency dependency of the effective power conversion factors shows periodic fluctuations at frequencies higher than the frequency corresponding to the wavelength. Furthermore, electric field intensities of electromagnetic wave emitted from metallic pair lines were investigated, when electric signals were fed to
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the normal mode circuit of pair lines, Relations between the effective power conversion characteristics and the electric field intensity characteristics were obtained.
Next, we defined equivalent ground plane at the place where conductor lines are installed, in order to obtain easily EMI phenomena in the construction such as reinforced building. And a method of searching the equivalent ground plane is proposed, which is applying the conversion characteristics of effective poer of TV feeder pair line obtained at low frequencies below several MHz.
(2) Propagation characteristics of effective electric power on two parallel metallic lines were clarified, one of which is inducing line and the other is induced line. It is shown that each magnitude of effective electric power on inducing line and induced line varies oscillatory along the line, and the total magnitude decreases gradually along the lines. This characteristics can be applied to the reduction method of unintended induction phenomena in which an effective absorbing line is installed besides the protected metallic conductor lines.
(3)The reduction characteristics of effective power propagating on common mode circuit between metallic lines and the earth were investigated, when a thin metal plate is put close to these lines partially. As a result, outstanding reduction effect is observed over several hundreds MHz when the thickness of the metal plate is quite less than skin depth at concern frequencies. This phenomena could be used as a reduction method of conducting noise on metallic lines and radiating noise from metallic lines installed in building or in the equipment.
These results could be helpful to introduce the suitable countermeasurement for information systems installed in buildings against electromagnetic interference problems. Less
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Research Products
(4 results)
