| Co-Investigator(Kenkyū-buntansha) |
YOSHIMURA Hiroyuki Chiba University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (90261354)
TAKAHASHI Masaharu Chiba University, Center for Frontier and Medical Engineering, Associate Professor, フロンティアメディカル工学研究開発センター, 助教授 (70267342)
SAITO Kazuyuki Chiba University, Center for Frontier and Medical Engineering, Research Associate, フロンティアメディカル工学研究開発センター, 助手 (80334168)
MIURA Amane Japan Aerospace Exploration Agency (JAXA), Researcher, 主任研究員 (10358939)
YAMAMOTO Shin-ichi Japan Aerospace Exploration Agency (JAXA), Researcher, 主任研究員 (50358933)
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| Research Abstract |
In this research, the development of an antenna system that can be used in Japan has been aimed in order to develop a basic technology for mobile satellite communications using a geostationary satellite. The contents of the research can be divided into the following three points :
1. Development of circularly polarized dual-band triangular-patch array antenna for both reception and transmission ;
2. Development of switching circuit and control system for satellite-tracking ;
3. Outdoor experiments of satellite communications using an experimental vehicle and a pseudo-satellite station.
To be more precise, in order to reduce the antenna dimensions in circular array configuration, a circularly polarized triangular patch antenna has been developed. Herewith, the antenna can be miniaturized and the gain at low elevation direction can be improved. The developed antenna element can easily be made in circular array configuration and along with its miniaturization, a configuration that allows a st
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able circularly polarized radiation by means of a dual feeding can be obtained.
When put into an array configuration, as both reception and transmission elements are combined in a single layer, a dual-band operation and good isolation characteristics are realized. In order to improve the radiation characteristics, the relative permittivity of the substrate, the element shape, and the distance between the elements are optimized.
A miniaturized control circuit based on ON-OFF method for satellite tracking and that does not make use of any phase shifter is developed aimed at an integration with the antenna. As the whole circuit can be implemented with chips components, a substantially integrated unit as well as low cost becomes possible.
Moreover, an automatic tracking system making use of a fiber optic gyro and personal computer is developed and a function enabling the control of the radiated beam depending on the direction of the vehicle is loaded. The antenna system is examined in the anechoic chamber to confirm the effectiveness of its performances.
In addition, to confirm the performances of the developed antenna under a real environmental conditions, a pseudo-satellite station is set on the roof of a building inside Chiba University, the characteristics of the antenna (1) when actually embarked in the experiment vehicle are investigated. The values of a budget link, for which the transmitted power and the operating frequency of the pseudo-satellite station are similar to the ones used for ETS-VIII, has been used.
In this research, it is confirmed by both numerical simulations and measurements that the antenna developed in this research is miniaturized, dual-band frequency operating, electrically tracking equipped from the antenna and overall system performances analysis.
Finally, these results are summarized and reported in the Technical Report of IEICE, the IEEE AP-S, and the Proceeding of the Institute of Image Information and Television Engineers. In addition, the results are also published in the IEICE Transactions on Communications (Japanese version) and the IEEE Transactions on Antennas & Propagation. Less
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