| Project/Area Number |
16K06365
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Communication/Network engineering
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| Research Institution | Chiba Institute of Technology |
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Principal Investigator |
CHO Keizo 千葉工業大学, 工学部, 教授 (00633356)
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| Co-Investigator(Kenkyū-buntansha) |
道下 尚文 防衛大学校(総合教育学群、人文社会科学群、応用科学群、電気情報学群及びシステム工学群), 電気情報学群, 准教授 (30535357)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2018: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | 移動通信 / 基地局アンテナ / 移相器 / メタマテリアル / CRLH伝送線路 / 周波数共用 / CRLH / 移動体通信 |
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| Outline of Final Research Achievements |
In multi-band mobile communication systems, the interference toward neighbor areas increases in low frequency band because current base station antennas usually operate in wide frequency bands then beam-width increases as the frequency decreases. We have proposed to apply composite right/left-handed (CRLH) transmission line that achieves large transfer phase in low frequency to the phase-shifter of the base station antennas to further tilt the beam direction in low frequency bands.
This study has focused on achieving large phase shift with small size. We have clarified that the amount of the phase shift can be double compared with a conventional configuration by varying both series capacitive and shunt inductive components. The circuit parameters that the Bloch impedance of the CRLH transmission line can be stable are also shown with maintaining the phase shift. Moreover, a concrete structure of the phase shifter is clarified by using finite element method analysis.
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| Academic Significance and Societal Importance of the Research Achievements |
移動通信は生活に必須な社会インフラとなり，日増しに増加する通信トラヒックを処理できる通信インフラの確保が重要となっている．一方無線通信に利用される電波の周波数は有限かつ貴重な資源であり，利用効率を最大限にまで高めることが求められている．本研究では，移動通信システム効率の劣化の要因となっている低周波数帯で生じる干渉を低減するために，メタマテリアルと呼ばれる自然界にはない材料をアンテナ部品に導入し，通常ではできない低周波数帯の放射方向をより傾けることができるアンテナを実現している．このような試みは世界でも例がなく，また周波数有効利用及びシステム効率向上に貢献できる社会的にも有用な技術である．
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