| Project/Area Number |
09450254
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
HOMMA Motofumi Graduate School of Engineering, Tohoku University, Professor, 大学院・工学研究科, 教授 (50005261)
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| Co-Investigator(Kenkyū-buntansha) |
KAGOTANI Toshio Graduate School of Engineering, Tohoku University, Res. Assoc., 大学院・工学研究科, 助手 (40005343)
SUGIMOTO Satoshi Graduate School of Engineering, Tohoku University, Assoc. Professor, 大学院・工学研究科, 助教授 (10171175)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥12,300,000 (Direct Cost: ¥12,300,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1998: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1997: ¥7,400,000 (Direct Cost: ¥7,400,000)
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| Keywords | barium M-type ferrite / electromagnetic wave absorber / substitutional elements / natural resonance / reflection loss / matching thickness / bandwidth / 電磁波吸収 / 磁気損失 / 磁気異方性磁界 / 磁気共鳴 / 六方晶フェライト / M型フェライト / 実効透磁率 / 複素透磁率 |
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| Research Abstract |
Purpose : Recently, wireless communication tools such as mobile telephones and computer local area networks (LAN), have become very popular. However, as the number of systems using high frequency electromagnetic waves has increased, serious electromagnetic compatibility (EMC) problems have become apparent. This has led to the search for electromagnetic wave absorption materials for the use in the GHz range. In this study, the electromagnetic microwave absorption properties of Barium Hexa and M-type ferrite, in which FeィイD13+ィエD1 was substituted by (MeィイD20.5ィエD2MnィイD20.5ィエD2)ィイD13+ィエD1(Me=Sn, Ti, Zr), were investigated in the GHz frequency range.
Experimental Procedure : Sintered samples were prepared by conventional powder metallurgy and composite samples were prepared by crushing these sintered bodies into powders (< 300μm) and mixing with an epoxy resin at different ratios from 40 to 80 mass%. The phases present in the samples were characterized by X-ray diffraction (XRD). The magnet
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ic properties were measured using a VSM and a magnetic balance. The electromagnetic wave absorption properties were measured using a Hewlett-Packard HP8510C network analyzer in the frequency range 0.05 to 20.05 GHz.
Results : The anisotropy field (HィイD2AィエD2) of Barium M-type ferrite can be changed by varying the TiィイD20.5ィエD2MnィイD20.5ィエD2 content, which enables the natural resonance frequency (fr) to be controlled, in the range 48 GHz to 8 GHz. BaFeィイD212-xィエD2(TiィイD20.5ィエD2MnィイD20.5ィエD2)ィイD2XィエD2OィイD219ィエD2 sintered ferrites with compositions x = 2.5 to 5 exhibited good microwave absorption properties, with minimum reflection losses (R.L.) less than -20 dB in 1 to 20 GHz frequency range, for matching thicknesses (dm) of 0.5 to 3.8 mm. The ferrite-resin composites with 70 mass% ferrite, exhibited wide bandwidths with R.L. < -20dB. In particular, the composite samples with compositions x = 3 and x = 4 had wide bandwidths of 14.1 to 〜20GHz and 7.4 to 12.0 GHz, for matching thicknesses of 1.6 mm and 2.7mm, respectively. These matching thicknesses were smaller than for conventional spinel ferrites. It may be concluded that Barium M-type ferrite is a good candidate for a thin electromagnetic microwave absorber in the GHz range. Less
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