The Study Of An Antenna For The Fourth Generation Maritime Satellite Communication

With the using of the forth generation satellite which is the part of the INMARSAT (International Maritime Satellite Organization), the satellite capacity increasing largely is 16 times of the third generation satellite. The business about the forth generation satellite communications also develops fast. At present, China's transport and communications centers launches BGAN (Broadband Global Area Network). This business has the full functions of the 3G mobile communications. Because the size and the bandwidth of the traditional maritime satellite antenna are difficult to meet the needs of design requirements about the BGAN's mobile terminals' functions like voice, video, internet etc, a new type antenna with small size and broadband is needed. This paper was based on the research item for the Beijing Yutong Technology Ltd. and the Dalian Maritime University Microwave Laboratory. The goal is to design a new type antenna using in the BGAN's mobile terminals which are used in the fourth generation maritime satellite communications.Based on the references, using the theory and simulation method, this paper designs a new type antenna using in the forth generation maritime satellite communications. The work includes the design of the unit antenna, the design of the antenna array and the design of the feed network.Firstly, based on the analysis of the single-fed circularly polarized rectangular microstrip antenna and the broadband multi-patch microstrip antenna, this paper designs a new type antenna unit used in the fourth generation maritime satellite communications. The antenna unit using the form of the single-fed circularly polarized dual-patch rectangular microstrip antenna has many advantages, like small, broadband, low-cost etc. The simulation and experiment results show that the technical indicators of the antenna unit meet the engineering requirements of the BGAN business.Secondly, based on the theory about the phased planar array of the microstrip antenna, this paper designs the planar array for the antenna unit which is used in the forth generation maritime satellite communications. The planar array is formed by 12 antenna units which are laid on the triangular grid and its maximum radiation direction isθ= 0°. The simulation results show that the planar array of the antenna units has many advantages like the high gain, the wide main petal angle, the low level of the minor petal etc.Thirdly, based on the theory about the powder divider, this paper designs the feed network for the antenna array which is used in the forth generation maritime satellite communications. The feed network is formed by the T-junction power dividers, the Wilkinson power divider and the microstrip transmission line. The simulation results show that the bandwidth of the feed network is about 40% and it meet the design requirement of the antenna which is used in the forth maritime satellite communications.