研究者詳細 - 藤森　和博

論文 - 藤森　和博

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A Metamaterial Mirror with Multiple CRLH Transmission Lines and its Imaging Quality 査読

Takuya Tsukagoshi, Kazuhiro Fujimori, Minoru Sanagi, Shigeji Nogi

2009 EUROPEAN MICROWAVE CONFERENCE, VOLS 1-3 201 - + 2009年

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

One-dimensional CRLH transmission lines are aligned to construct two-dimensional medium with imaging capability not found in homogeneous materials. Mimicking electromagnetic field distribution on a surface of the perfect lens, high resolution imaging is demonstrated. Unlike transmission configurations such as in a lens, the imaging operation proposed in this paper is not disturbed by dissipation or index mismatch, leading to wide band operations.

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Development of Ultrasonic Wireless Power Transmission System for Implantable Electronic Devices 査読

Yusuke Shigeta, Tsunayuki Yamamoto, Kazuhiro Fujimori, Minoru Sanagi, Shigeji Nogi, Takuya Tsukagoshi

EUWIT: 2009 EUROPEAN WIRELESS TECHNOLOGY CONFERENCE 49 - + 2009年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

In recent years, the development of the in-vivo medical devices are remarkable. Generally, in-vivo devices need the internal battery. The life of internal battery is limited, and the maintenance of the battery is necessary.
For overcoming this problem, the ultrasonic wireless power transmission technology is studied. In the past reports, the transducer of ultrasonic wireless power transmission system is not designed for electrical matching with input source, amplifier circuit, and rectification circuit, etc.
In this paper, we propose the efficient ultrasonic wireless power transmission system. For realizing the efficient system, the impedance matching between the input source, amplifier circuit and the ultrasonic transducer is considered. And the optimum position of two transducers necessary for achieving a high transmission efficiency is searched. Moreover, the voltage booster circuit to obtain the high DC oputput voltage is designed. In the transmission experiment, it is confirmed that the high DC output voltage for the operation of the in-vivo devices is achieved.

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Development of high efficiency rectification circuit for mW-class rectenna 査読

Kazuhiro Fujimori, Kazuya Tada, Yusuke Ueda, Minoru Sanagi, Shigeji Nogi

35th European Microwave Conference, Vols 1-3, Conference Proceedings 1355 - 1358 2005年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：HORIZON HOUSE PUBLICATIONS LTD

For applications of the microwave power transmission technology, it is necessary to realize high efficiency rectennas or rectification circuits. Especially, RF-ID's or ubiquitous power sources demand high RF-DC conversion efficiency for below, mW microwave inputs. However, almost all past rectennas or rectification circuits were designed for over 100 mW rectifying and the RF-DC conversion efficiencies were less than 20% at 1mW microwave input. In this paper, we investigate rectification circuits for developing mW-class rectennas. Discussing diode mount structures in order to increase the efficiency below 10 mW microwave input, we succeeded in developing a rectification circuit whose efficiency is 62.8% for a 10 mW microwave input. We also find that approximately 30% of the input microwave power is consumed by the diode in the rectification circuit.

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Chain power divider/combiner with microstrip line probes inserted into a rectangular waveguide 査読

M Sanagi, S Ekuni, K Fujimori, S Nogi

PROCEEDINGS OF THE 2004 CHINA-JAPAN JOINT MEETING ON MICROWAVES 41 - 44 2004年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：HARBIN INSTITUTE TECHNOLOGY PUBLISHERS

Multiple-way power divider/combiner's with a rectangular waveguide port for input/output signal and microstrip line ports for output/input signals are presented. A number of dividing/combining units are successively connected in the chain structure. The unit is composed of the rectangular waveguide section with the microstrip-line probe pair and the thin narrow section. Using as the divider, the chain structure has wideband performance due to the traveling-wave opeartion. High isolation between the paired ports in the unit is established by connecting the paired microstrip lines via a chip resistor. The four-way divider/combiner operating at X-band is designed. The broadband characteristics and. high isolations among the furcated ports are confirmed by the prototype divider/combiner.

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Indoor propagation characteristics including radiation pattern and polarization of base station 査読

K Fujimori, H Arai

IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 2006 - 2009 1997年

Experimental study of indoor propagation characteristics including radiation pattern and polarization of base station 査読

K Fujimori, H Arai

1997 ASIA-PACIFIC MICROWAVE CONFERENCE PROCEEDINGS, VOLS I-III 1217 - 1220 1997年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：CITY UNIVERSITY HONG KONG

In this paper, we conduct propagation measurements focusing on the radiation pattern and the polarization of base station antennas under the line of sight(LOS) and no LOS environments. We measured and investigated propagation characteristics inside them, and we confirmed that propagation characteristics inside passages are depended on its cross sectional shape and that a attenuation coefficient is changed by the radiation pattern and the polarization of the base station antenna.

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Polarization characteristics under indoor micro/pico cell environments

Kazuhiro Fujimori, Hiroyuki Arai

IEE Conference Publication ( 436 ) 2.305 1997年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEE

An investigation of the polarization characteristics of the cellular radio system for wireless local area network inside a corridor confirmed that the horizontal polarization forms a large electric field distribution rather than the vertical polarization. Moreover, the optimum polarization to obtain a smaller attenuation coefficient is a horizontal polarization excited by the flat antenna which has nulls toward floor and ceiling. The field distributions obtained by the ray tracing analysis agree with the experiments. The optimum polarization is determined by the cross section of the corridor and the radiation pattern of the base antenna.

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Ray tracing analysis of propagation characteristics in tunnels including transmitting antenna 査読

K Fujimori, H Arai

IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM - 1996 DIGEST, VOLS 1-3 1222 - 1225 1996年

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