Design of Multibeam Antenna System for Winds
- Paper number
IAC-06-B3.4.03
- Author
Dr. Satoru Ozawa, Japan Aerospace Exploration Agency (JAXA), Japan
- Coauthor
Mr. Yoichi Koishi, NEC Toshiba Space Systems, Ltd., Japan
- Year
2006
- Abstract
JAXA has been developing a multibeam antenna system for mounting on WINDS, the wideband inter-networking engineering test and demonstration satellite, slated for launch in 2008. The satellite uses 1.1GHz bandwidth in Ka frequency band, and its mission is primarily to provide a high speed communication to ground stations at 1.2Gbps. The satellite consists of a multibeam antenna system and a multiport amplifier for high speed communications, an active phased array antenna, and a regenerative ATM baseband switch. The multibeam antenna system is one of the key technologies for meeting WINDS missions. The mission requirements for the antenna system are (i) to provide communication to 19 areas, (ii) to transmit at an 18GHz frequency band and to receive at a 28GHz frequency band, and (iii) to communicate with 45cm small aperture antennas at 155Mbps as well as 5m at 1.2Gbps. The antenna system consists of two main reflectors that provide communication in 12 areas in Japan and 7 others in Asia Pacific, a total of 19 feeds targeting each communication area, a polarization separation grid panel for stowing the feeds in limited space, and a truss structure for supporting these components. In this paper, we would like to address the design of the components proposed to achieve the requirements of the multibeam antenna system. The main reflectors need to satisfy specific RF requirements. We discovered difficulties in estimating the RF performance due to the reflector’s unpredictable deformation. In order to grasp the precise reflector’s deformation, we have measured thermal deformations of the reflector in a thermal vacuum chamber by using the photogrammetry technique. We have also carried out a RF radiation test of the polarization separation grid panel. We have designed this high-precision panel for use in Ka frequency band. In addition to the RF radiation test, we have measured RF patterns of the multibeam antenna system and then verified the panel’s validity. We have also performed vibration tests and thermal balance tests of the antenna system and confirmed its validity. Through these tests, we have confirmed that the antenna system meets its requirements. Therefore, we expect the multibeam antenna system to realize its future space missions as an important subsystem of WINDS.
- Abstract document