【作者】 刘健；

【导师】 鄢泽洪； 杜晓勇；

【作者基本信息】 西安电子科技大学 ， 电子与通信工程， 2014， 硕士

【摘要】 随着移动通信技术的快速发展,“动中通”天线系统已被广泛应用于各种通信领域。传统的基于机械扫描“动中通”天线由于跟踪精度低、反应时间长、价格昂贵以及故障率高等因素,极大的限制了它的应用。如何提高“动中通”天线系统的各项性能,且降低成本,是本文重点研究的内容。相控阵天线是一种新型的电控波束扫描“动中通”天线。由于其本身波束快速扫描,波束指向精度高,且易于与平台共形等特点被广泛应用。对相控阵天线而言,天线单元的设计、天线阵列方向性分析、移相器性能及基于天线阵的波束控制系统是相控阵天线系统几个关键技术。本文针对天线单元和天线阵列,移相器及波束控制系统做了分析与研究。根椐工程应用需要,设计了一个低成本、小型化的相控阵天线系统。本文的主要工作如下:1)天线阵列的设计。根椐天线的加载原理,使用金属圆盘加载的方法,对天线单元进行良好匹配的同时,也降低了天线的高度,实现了低轮廓、宽频带、圆极化螺旋天线单元。通过调整天线阵结构,改变各天线单元的馈电相位,实现了波束扫描,并使天线在低仰角,也有较高的增益和较好的不圆度。2)移相器的设计。根椐移相器的基本原理,对各类移相电路形式进行了分析和比较,为每一个移相单元选择了合适的移相电路形式。即45?、90?选择开关线型移相电路,180?选择反射型移相电路,这样能尽可能的减小相移误差。通过选择合适的PIN二极管和介质板,能实现移相器的小型化。同时对级连的各移相单元采用金属化通孔的隔离方法,能减小各移相单元间相互影响。3)波束控制系统的设计。波束控制系统的主要功能是采集通信卫星和天线载体的位置信息。根椐电子罗盘对天线载体实时运动状态信息的反馈,通过控制移相器的移相值,改变天线阵列的波束指向,从而实现波束扫描。且能根椐实际需要,实现不同工作模式之间的切换,即波束自动跟踪模式、波束快速扫描模式[1]。更多还原

【Abstract】 With the rapid development of mobile communication technology, the on-the-move communication antenna system has been widely used in various communication fields. The traditional mechanical scanning on-the-move antenna has the characteristics of low tracking accuracy, long reaction time, high prices and high failure rate, which greatly limit its application. How to improve the performance of on-the-move antenna system and reduce the costs are the key researches included in this paper.Phased array antenna is a new electronically controlled beam scanning on-the-move antenna. It is widely used for its own characteristics of rapid beam scanning, high beam pointing accuracy, and easy conformal characteristic. For the phased array antenna, the design of antenna unit, the directional analysis of antenna array, the performance of the phase shifter and the beam control system based on the antenna array are the key techniques in the phased array antenna system. In this paper, the antenna unit, the antenna array, the phase shifters and the beam control system are analyzed and researched. Based on the need of engineering applications, we design a low-cost and miniaturized phased array antenna system. The main contents of this paper are summarized as follows.1) Design of antenna array. According to the loading principle of antenna, and by using metal disc loading method, something is done to get a good match of the antenna unit, and to reduce the height of the antenna, resulting in a low profile, wide bandwidth and circularly polarized helical antenna unit. By adjusting the structure of the antenna array and changing the feeding phase of each antenna unit, the beam scanning is realized, and the antenna is made to have a high gain and good roundness though at a low elevation.2) Design of phase shifter. According to the basic principles of phase shift, various types of phase shift circuits are analysized and compared, and the appropriate phase-shift circuit form is selected for each phase shifting unit. Select switch linear phase shift circuit is selected for 45 degrees and 90 degrees, and reflection-type phase shifter circuit for 180 degrees, which can reduce the phase shift error as much as possible. By selecting an appropriate PIN diode and dielectric plate, the phase shifter can be miniaturized. Meanwhile, by using the isolation method based on plated through-hole for cascaded phase shifting unit, the impact of each shift inter-phase units can be reduced.3) Design of the beam control system. The main function of beam control system is to collect location information of the communication satellite and the antenna carrier. According to the feedback information of the electronic compass about the motion of antenna carrier at a real time, the system control the phase shift value of phase shifter and changing the beam direction of antenna array, which can realize the beam scanning. And based on the actual need, the beam control system can switch between different operating modes, namely, automatic beam tracking mode and rapid beam scan mode.更多还原