Design Of Maritime Satellite Communications Circularly Pol-arized Stereoscopic Antenna Array

With the development of information technology and the demand for high performance antenna, the previous linearly polarized antennas are very difficult to meet the people’s needs. Circularly polarized microstrip antenna combines the advantages of microstrip antenna such as compact structure, small size, light weight, low profile, easy fabrication, easy integration, easy to be attached to any surface and the advantages of circularly polarized wave such as suppress the interference of rain and fog, anti-multipath reflection, better mobility. So circularly polarized microstrip antenna has been widely used in satellite communications, radar, mobile communications and a variety of wireless communication devices.Presently, many researches have been done on the antenna array, but they mainly concentrate in the linear array and plane array. Linear array and plane array have the advantages of convenient layout, strong regularity, as well as easy control and debug the characteristic parameters. However, they can’t realize half space or total space radiation, for the gain is larger only in the radiation direction. The tridimensional array can solve this problem.The paper mainly aim at the research of the feed network, the polarized antenna feed form and the antenna array design, with the background of maritime satellite communication system and on the basis of summarizing the predecessors’ achievements, and designed three types of feed network, two coupled feed circular polarization antenna and a tridimensional array.ntenna. The main work of the paper is as follows:(1) Introduce the characteristic parameters of the microstrip antenna, and the techniques for realizing the broad-band and circular polarization microstrip antenna.(2) Design a90°broadband phase shift power divider based on the Wilkinson power divider. The performance is good but the layout is complex. To solve this problem, a T type power points phase shifter and an orthogonal (90°) hybrid network are designed.(3) Design two dual-feed circularly polarized antennas, one with the T type power points phase shifter network and coupled feeding, the other with the orthogonal (90°) hybrid network probe feed, according to the result of the feed network research. The circular polarized antenna with coupled feeding owns good performance, convenient debugging, and broad research and application prospects.(4) Propose a pyramid circular polarized tridimensional antenna array, through the research and analysis of the antenna array at home and abroad. The tridimensional array can realize half space radiation, with high gain, and it is suitable for the maritime satellite communications system.