Ultra-Lightweight 20m Antenna Reflector and Light-weight 100 Beam Class Feed System for Future Mobile Broadband Communications Satellites

Paper number

IAC-06-B3.2.07

Author

Mr. Satoshi Harada, NTT Access Network Service System Laboratories, Japan

Coauthor

Dr. Yoshinori Suzuki, NTT Access Network Service System Laboratories, Japan

Coauthor

Dr. Akira Meguro, Japan Aerospace Exploration Agency (JAXA), Japan

Coauthor

Dr. Masazumi Ueba, NTT Access Network Service System Laboratories, Japan

Year

2006

Abstract

This paper introduces a future broad-band scalable mobile communication satellite system that will be able to offer economical broadband Internet services by around 2010. The system would be used for bridging terrestrial broadband digital divide, mitigating disasters and monitoring the environment, by using small/portable terminals. The system should be constructed to 1) greatly enhance satellite capacity up to 1 Gbps, using high performance on-board equipment on a 1-ton-class geostationary satellite, 2) utilize the capacity efficiently to accommodate varying traffic conditions, and 3) handle a wide range of speeds, scalable from 1 kbps up to 100 Mbps in a single system. This paper describes a feasibility study of the enabling technologies.

To lower the costs and extend satellite communication market, we must dramatically increase the performance of commercial satellite systems suppressing cost of the satellite. Our success scenario for the construction of an economical satellite system is to embark 100 beams-class multi-beam satellite communication equipments on one or one-half ton class satellite bus system. 

Three major technologies are important to achieve the proposed system. The first one is an ultra light-weight large antenna reflector, whose aperture diameter is larger than 20m and whose areal density is less than 0.25 kg/m2. Target total mass is 130 kg including the boom structure and holding structure. To realize this new reflector antenna, we proposed a geodesic cable network system supported by a tendon structure. From research conducted over the last two years, we have concluded that large deployable mesh antenna reflectors, whose aperture is 20m and whose weight is around 130 kg, appear feasible. The second is a multi-beam antenna feed system. The feed system consists of 64 radiation elements, solid state amplifiers with variable phase-shifter, and passive beam forming network. The feed system can form 69 beams, whose RF power can be controlled for a corresponding traffic conditions by overlapping beam groups. Beam pointing errors and a focusing error can be corrected by using the phase-shifter. The last one is orthogonally arranged frequency converter. We confirmed that we can effectively reduce total weight of a satellite system by using theses compositions.

Abstract document

IAC-06-B3.2.07.pdf

Manuscript document

IAC-06-B3.2.07.pdf (🔒 authorized access only).

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