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[Author] Satoru KUROKAWA(4hit)

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  • Standardization Activities for Radio on Fiber Transmitter within IEC TC103/WG5 Open Access

    Satoru KUROKAWA  Junichiro ICHIKAWA  Tetsuya KAWANISHI  Hiroyo OGAWA  

     
    INVITED PAPER

      Vol:
    E96-C No:2
      Page(s):
    138-146

    This paper describes the outline of recent standardization activities for Radio on Fiber (RoF) transmitter by IEC TC103/WG5. RoF transmitter consists of optical fibers, electrical to optical (E/O) converter, and optical to electrical (O/E) converter. IEC TC103/WG5 is working on standardization on measurement method of E/O and O/E devices, and technical specification of RoF transmitter. This paper overviews those standardization activities which are being developed by TC103/WG5 as well as the National Committee of WG5.

  • A Design Scheme for Electromagnetic Shielding Clothes via Numerical Computation and Time Domain Measurements

    Satoru KUROKAWA  Toru SATO  

     
    PAPER

      Vol:
    E86-C No:11
      Page(s):
    2216-2223

    Electromagnetic shielding clothes for reducing human exposure to radio waves have been commercialized. However, their effect has so far been confirmed only in the form of the raw material. In this paper, we develop a new compact scheme for measuring electromagnetic radiations using a short dipole antenna and Gaussian pulses in order to evaluate the effect of the shielding clothes over a wide frequency range with the aid of time-domain measurements and FDTD computation. The proposed method is based on a time-domain analysis technique and pulse compression technique, which enables the user to separate the direct transmission wave from the reflection from the floor as well as from the refracted wave around the neck of the clothes. The direct advantage is that measurements can be made in an ordinary laboratory without the function of an electromagnetic anechoic chamber. Also, we can separate direct transmission wave and diffraction wave from the measurement result by using pulse compression technique, then each frequency characteristic of the shielding shirt can be evaluated. The performance of the separation is confirmed by comparing the measurements with those of a shirt with no opening. We further demonstrate the possibility of predicting the effective conductivity of the material as a function of frequency by comparing the measured results with realistic FDTD computations, which will enable us to design a shielding shirt via numerical means.

  • Antennas Measurement for Millimeter Wave 5G Wireless Applications Using Radio Over Fiber Technologies Open Access

    Satoru KUROKAWA  Michitaka AMEYA  Yui OTAGAKI  Hiroshi MURATA  Masatoshi ONIZAWA  Masahiro SATO  Masanobu HIROSE  

     
    INVITED PAPER

      Pubricized:
    2023/09/19
      Vol:
    E106-B No:12
      Page(s):
    1313-1321

    We have developed an all-optical fiber link antenna measurement system for a millimeter wave 5th generation mobile communication frequency band around 28 GHz. Our developed system consists of an optical fiber link an electrical signal transmission system, an antenna-coupled-electrode electric-field (EO) sensor system for 28GHz-band as an electrical signal receiving system, and a 6-axis vertically articulated robot with an arm length of 1m. Our developed optical fiber link electrical signal transmission system can transmit the electrical signal of more than 40GHz with more than -30dBm output level. Our developed EO sensor can receive the electrical signal from 27GHz to 30GHz. In addition, we have estimated a far field antenna factor of the EO sensor system for the 28GHz-band using an amplitude center modified antenna factor estimation equation. The estimated far field antenna factor of the sensor system is 83.2dB/m at 28GHz.

  • A Simply Structured Transverse Slot Linear Array Antenna in a Quasi-TEM Mode Waveguide

    Yuanfeng SHE  Masanobu HIROSE  Yuto KATO  Takayuki ISHIZONE  Satoru KUROKAWA  Shinya IWASAWA  Sintaro ARATA  

     
    BRIEF PAPER

      Vol:
    E100-C No:10
      Page(s):
    924-927

    This article proposes a simply structured transverse slot linear array antenna with a low cross-polarization in X band on a quasi-TEM (transverse electromagnetic) mode waveguide. The fabrication technology of this antenna is very simple and suitable for mass production. A center fed linear slot array has been designed and measured. The quasi-TEM wave is propagating in the conventional waveguide with dielectrics at sidewalls. The simulation and the measurement results show that the baffle plates enhance the gain and reduce the beamwidth effectively. The uncertainties of the electric properties of the dielectric and fabrication errors are also discussed.