研究者詳細 - 藤森　和博

MISC - 藤森　和博

分割表示 164 件中 61 - 80 件目／全件表示 >>

Negative Refraction and Energy-Transmission Efficiency of Acoustic Waves in Two-Dimensional Phononic Crystal: Numerical and Experimental Study

Yuuki Kasai, Kenji Tsuruta, Kazuhiro Fujimori, Hideki Fukano, Shigeji Nogi

JAPANESE JOURNAL OF APPLIED PHYSICS 50 ( 6 ) 2011年6月

記述言語：英語出版者・発行元：JAPAN SOC APPLIED PHYSICS

The negative refraction of acoustic waves in a two-dimensional phononic-crystal slab is studied by numerical simulation based on the finite-difference time-domain (FDTD) method and by ultrasonic measurement. The incident-angle dependences of energy-transmission efficiency in the simulation and experiment are in good agreement in the frequency range of approximately 1.2 MHz. Using the FDTD method, we optimize the efficiency by varying structural parameters such as filling fraction and slab thickness. The effect of deviation from the ideal crystallinity is also evaluated quantitatively via the simulation. These results indicate that an energetically efficient acoustic lens can be fabricated by carefully optimizing the structure of the phononic crystal. (C) 2011 The Japan Society of Applied Physics

DOI： 10.1143/JJAP.50.067301

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C-2-65 矩形導波管中に挿入した同軸プローブ対の等価回路(C-2.マイクロ波B(マイクロ波・ミリ波受動デバイス),一般セッション)

佐薙稔, 藤森和博, 野木茂次

電子情報通信学会総合大会講演論文集 2011 ( 1 ) 103 - 103 2011年2月

Acoustic lens using sonic crystal for energy-transmission application

Y. Kanno, Y. Kasai, K. Tsuruta, K. Fujimori, H. Fukano, S. Nogi

2011 IEEE MTT-S International Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications, IMWS-IWPT 2011 - Proceedings 207 - 210 2011年

記述言語：英語

We design and characterize a two-dimensional sonic crystal (SC) to manipulate the propagation of acoustic waves by numerical simulation based on the finite-difference time-domain (FDTD) method and by ultrasonic measurement. Two types of SC for an acoustic lens effect are studied. One is a homogeneous periodic structure exhibiting negative refraction, and the other has a hetero-structure. Negative refraction behavior in the simulation is good agreement with the experiment in the frequency range around 1.2MHz. We also observe a lens effect for far-field wave in the hetero-structured SC. These results indicate that a novel energy-transmission/harvesting device can be designed using SCs. © 2011 IEEE.

DOI： 10.1109/IMWS.2011.5877131

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Development of highly efficient transducer for wireless power transmission system by ultrasonic

Yusuke Shigeta, Yuki Hori, Kazuhiro Fujimori, Kenji Tsuruta, Shigeji Nogi

2011 IEEE MTT-S International Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications, IMWS-IWPT 2011 - Proceedings 171 - 174 2011年

記述言語：英語

We developed a fundamental testbed and investigated the suitable transducer for the wireless power transmission (WPT). We also reported experimental results of the transmission efficiency in water by using the commercial transducer (COM) which only designed to match to the acoustic impedance of water and the electric impedance of the transmitter and receiver. In this paper, we investigate the transducer for improving the efficiency based on the Mason's equivalent circuit. For deciding a structure and materials of the transducer, we used ANSYS well-known as the multi-physics simulator. In this result, it is confirmed that the transmission efficiency is drastically improved from less than 1% to 60%. In addition, we made designed transducer, and confirmed the systems' efficiency is about 50 %. This result suggests that the WPT by acoustic wave is practicable. © 2011 IEEE.

DOI： 10.1109/IMWS.2011.5877115

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導波管ポートと同軸線路ポートをもつ回路素子の散乱行列の未知スルー校正法を用いた測定(共著)

佐薙稔, 藤森和博, 野木茂次

電子情報通信学会論文誌(C) J94-C ( 12 ) 487 - 495 2011年

Design of Anti-Resonance Transducer and Its Abilities for Efficient Ultrasonic Wireless Power Transmission System

Yuki Hori, Yusuke Shigeta, Kazuhiro Fujimori, Kenji Tsuruta, Shigeji Nogi

2011 41ST EUROPEAN MICROWAVE CONFERENCE 67 - 70 2011年

記述言語：英語出版者・発行元：IEEE

We developed a fundamental testbed and investigated the suitable transducer for the wireless power transmission (WPT). We also had reported experimental results of the transmission efficiency in water by using the commercial transducer (COM) which only designed to match to the acoustic impedance of water by its structure and the electric impedance of the transmitter and receiver by matching networks. In this paper, we investigate the transducer (DEV) for improving the transmission efficiency based on the Mason's equivalent circuit. For deciding a structure and materials of the transducer, we used ANSYS well-known as the multi-physics simulator.
In this result, it is confirmed that the transmission efficiency is drastically improved from less than 1% to 60% compared to our previous report. In addition, we manufactured designed transducer, and confirmed the system's efficiency is about 50 % experimentally. This result also suggests that WPT by the acoustic wave be practicable.

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The Influences of Diode Parameters on Conversion Efficiency of RF-DC Conversion Circuit for Wireless Power Transmission System

Kazuhiro Fujimori, Sho-ichi Tamaru, Kenji Tsuruta, Shigeji Nogi

2011 41ST EUROPEAN MICROWAVE CONFERENCE 57 - 60 2011年

記述言語：英語出版者・発行元：IEEE

RF-DC conversion circuit is one of the most important components in the wireless power transmission technologies. For realizing highly efficient wireless power transmission, it is necessary to design the RF-DC conversion circuit with high conversion efficiency, and the designing method of the circuit is actively studied. In this paper, the influences of diode parameters, such as its resistance, junction capacitance, parasitic reactance, and so on, on the conversion efficiency of the RF-DC conversion circuit are investigated to clarify the characteristic of the diode for obtaining highly efficient RF-DC conversion circuit.

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Efficiency and harmonics generation in microwave to DC conversion circuits of half-wave and full-wave rectifier types

Shohei Imai, Shoichi Tamaru, Kazuhiro Fujimori, Minoru Sanagi, Shigeji Nogi

2011 IEEE MTT-S International Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications, IMWS-IWPT 2011 - Proceedings 15 - 18 2011年

記述言語：英語

A Rectifying Antenna (Rectenna) is one of the most important components for a wireless power transmission. It has been developed for many applications such as Space Solar Power System (SSPS), and Radio Frequency Identification (RFID) etc. The Rectenna consisting of RF-DC conversion circuits and receiving antennas needs to be designed for high conversion efficiency to achieve efficient power transmission. we try to design the mw-Class RF-DC conversion circuit using half-and full-wave rectification. The measured conversion efficiencies is 59.3 % and 65.3 % athalf- and full-wave type, respectively. And the full-wave type has lower 2nd harmonic reflection coefficient. © 2011 IEEE.

DOI： 10.1109/IMWS.2011.5877081

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フォノニック結晶による超音波の音響レンズ効果とエネルギー輸送効率

菅野祐輔, 笠井祐樹, 鶴田健二, 藤森和博, 深野秀樹, 野木茂次

日本機械学会計算力学講演会論文集(CD-ROM) 24th 2011年

半導体結晶表面における弾性波伝搬の大規模分子動力学シミュレーション

藥師川裕貴, 鶴田健二, 藤森和博

日本機械学会計算力学講演会論文集(CD-ROM) 24th 2011年

導波管ポートと同軸線路ポートを持つ回路素子の散乱行列の未知スルー校正法を用いた測定

佐薙稔, 藤森和博, 野木茂次

電子情報通信学会技術研究報告. MW, マイクロ波 110 ( 343 ) 23 - 28 2010年12月

記述言語：日本語出版者・発行元：一般社団法人電子情報通信学会

導波管ポートと同軸線路ポートを持つ回路素子の散乱行列要素の測定について検討した.ネットワークアナライザの同軸線路テストポートを導波管に変換するための変換器の特性を求めるために未知スルー校正法を用いた.校正の過程において,未知スルーとして用いる回路の透過係数の位相の値が±90°の精度で必要となる.そこで,未知スルーとして用いる同軸一導波管変換器を電磁界シミュレータを用いて設計し,計算された透過係数の位相の値を必要な既知の値とした.試作した変換器を用いて,導波管中に同軸プローブを挿入した回路素子の散乱行列要素の測定を行った.

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Design of Highly Efficient and Compact RF-DC Conversion Circuit at mW-class by LE-FDTD Method(共著)

Tsunayuki Yamamoto, Kazuhiro Fujimori, Minoru Sanagi, Shigeji Nogi

The IEICE Transactions on Electronics E93C ( 8 ) 1323 - 1332 2010年8月

RF to DC Conversion for Wireless Power Transmission

Shigeji Nogi, Kazuhiro Fujimori, Minoru Sanagi

The IEICE Transactions on Electronics J93-C ( 12 ) 540 - 548 2010年

An Important Relation for Determining A High-Efficiency RF–DC Conversion Circuit(共著)

Shohei Imai, Kazuhiro Fujimori, Minoru Sanagi, Shigeji Nogi

2010 Asia-Pacific Microwave Conference 2319 - 2322 2010年

無線電力伝送におけるRF-DC変換(共著)

野木茂次, 藤森和博, 佐薙稔

電子情報通信学会誌 J93-C ( 12 ) 540 - 548 2010年

同軸線路ポートと導波管ポートを持つ回路素子の測定のためのネットワークアナライザの校正

佐薙稔, 吉岡秀浩, 小路宗博, 藤森和博, 野木茂次

2010信学総大, March 163 - 163 2010年

C-2-39 広帯域な円筒形多分岐電力分配/合成器の分岐数に依存しない設計(C-2.マイクロ波B(マイクロ波・ミリ波受動デバイス),一般セッション)

鎌田裕之, 佐薙稔, 藤森和博, 野木茂次

電子情報通信学会総合大会講演論文集 2009 ( 1 ) 78 - 78 2009年3月

C-2-33 処理する高調波数が有限な場合の逆C級周波数2逓倍動作(C-2.マイクロ波A(マイクロ波・ミリ波能動デバイス),一般セッション)

岸田武紘, 佐薙稔, 藤森和博, 野木茂次

電子情報通信学会総合大会講演論文集 2009 ( 1 ) 72 - 72 2009年3月

Efficient antenna miniaturization technique by cut off of chromosome-length in genetic algorithm(共著)

Tsunayuki YAMAMOTO, Kazuhiro FUJIMORI, Minoru SANAGI, Shigeji NOGI, Takuya TSUKAGOSHI

2009 Asia-Pacific Microwave Conference 1837 - + 2009年

広帯域な同軸-コニカル-ラジアル線路変換部をもつ円筒型多分岐電力分配/合成器

鎌田裕之, 佐薙稔, 藤森和博, 野木茂次

電子情報通信学会技術研究報告. MW, マイクロ波 108 ( 350 ) 91 - 96 2008年12月

記述言語：日本語出版者・発行元：一般社団法人電子情報通信学会

マイクロ波高出力固体増幅器を実現する方法の一つとして電力分配-合成系があるが、これに必要となる広帯域かつ低損失な特性を持つ電力分配/合成器として、広帯域な同軸-コニカル-ラジアル線路変換部を持つ円筒形電力分配/合成器について検討した。電力分配/合成器は同軸-コニカル-ラジアル線路変換部である中心部と、ラジアル線路中に同軸プローブを挿入した周辺部とで構成される。変換部では同軸線路から2段階のコニカル線路を経てラジアル線路に変換する。ラジアル線路の特性インピーダンスは虚部を持つので2段階目のコニカル線路を4分の1波長変成器のような整合線路として用いる。それにより、より広い周波数範囲で、より低い反射を有する変換器が設計できる。試作した12分配電力分配器の特性を測定することで本設計手法の有効性を確認した。

<藤森 和博>

MISC - 藤森 和博

<藤森　和博>

MISC - 藤森　和博