【作者】 付世强；

【导师】 房少军；

【作者基本信息】 大连海事大学 ， 通信与信息系统， 2010， 博士

【摘要】 随着信息技术的发展,对天线性能的要求也越来越高,以往单纯的线极化天线已很难满足人们的需求。圆极化微带天线由于结合了微带天线诸如结构紧凑、体积小、重量轻、剖面低、容易制造、易于集成并可附着于任意表面等优点和圆极化波能够抑制雨雾的干扰、抗多径反射、具有更好的移动性等优点,目前已广泛应用于卫星通信、雷达、移动通信以及各种无线通信设备当中。BGAN是宽带全球区域网的英文缩写,是国际海事卫星组织耗资15亿美元打造的第四代全球性卫星移动通信系统。它吸取、兼容了3G的通信优势,在卫星通信中结合了便携移动、宽带、网络通信的需求,成为向在全球范围内任意移动的用户提供安全可靠的音视频流媒体传输、电子邮件、网络接入服务的革命性通信系统。凭借所发射的最尖端的商业通信卫星,BGAN可以通过非常小巧的用户终端和简易的操作方式以合理的价位为用户提供速率高达492kbps的移动宽带服务。天线作为其终端设备收发信号的部件,对通信质量好坏起着至关重要的作用。本文以BGAN系统陆地便携移动终端天线为工程应用背景,在总结前人研究的基础上,主要针对微带天线的宽频带和圆极化技术展开研究,采用理论计算、数值仿真和实验验证相结合的方法,设计了几款适用于BGAN终端的宽带圆极化微带天线。本文的主要工作如下：(1)介绍了微带天线的性能参数以及微带天线实现宽频带、圆极化和链路匹配的关键技术。系统阐明了微带天线实现圆极化工作的基本原理和提升圆极化性能的改进方法。(2)重点讨论了本文所用的电磁数值仿真算法—有限元法以及工程优化算法—田口方法(Taguchi’s method),并将基于有限元法的Ansoft HFSS软件和基于正交试验设计的Taguchi’s method二者相结合,实现了GPS微带天线的优化设计。(3)通过对单馈电圆极化微带天线技术的分析与研究,提出了一款适用于BGAN系统陆地便携移动终端Class-2天线结构,并通过仿真和实验进行了验证。实测结果表明,天线在海事卫星通信工作频段内具有较好的圆极化辐射特性,其驻波比小于1.2,增益高于13dB,测试值与仿真值一致性较好。该天线具有体积小、重量轻,结构紧凑、制作简单,便携可移动等特点,其应用前景广阔。(4)通过对双馈电圆极化微带天线技术的分析与研究,提出了一款适用于BGAN系统陆地便携移动终端Class-1天线结构,并通过仿真和实验进行了验证。实测结果表明,天线在整个海事卫星通信工作频带内有较好的特性,驻波比小于1.35,增益高于14dB,3dB宽角轴比达40°,实测值与计算值具有较好的一致性。该天线具有宽带宽、高增益和宽角圆极化等特点,在整个海事卫星通信工作频段能高质量、高效率地实现信号的发射与接收。设计的天线已成功地应用于HNS9201户外移动终端,验证了该设计方案的可行性。该天线具有成本低廉,加工简单,适合大批量生产制作等优点,为海事卫星通信BGAN地面移动终端提供了一种实用的收发天线。(5)通过对多元组合馈电圆极化微带天线技术的分析与研究,提出了一款应用于L波段卫星通信的宽带圆极化微带缝隙天线,并通过仿真和实验进行了验证。实测结果表明,天线工作于L波段时,增益达到8dB,驻波比小于1.5的阻抗带宽和轴比小于3dB的圆极化带宽分别达到了52%和49%。天线具有较好的圆极化辐射特性。设计的天线结构简单、尺寸紧凑,价格低、带宽宽,具有很高的实用价值。该天线同样适用于海事卫星通信低速数据小型终端。更多还原

【Abstract】 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.BGAN is an abbreviation of Broadband Global Area Network, which is a fourth-generation global satellite mobile communications system built by INMARSAT costing over 1.5 billion dollars. It is compatible with the 3G communication and combined with mobile, broadband, network communication needs in satellite communications. It is a revolutionary communications system which can provide users around the world with secure and reliable transmission of audio and video streaming, e-mail, internet access services. With the launch of the most sophisticated commercial communications satellites, BGAN can provide users with speeds up to 492kbps for mobile broadband services using a very small user terminal at a reasonable price. Antennas, as part of its terminal equipment components, play a vital role in communication quality.This paper is set in BGAN system portable mobile terminal antennas for engineering applications. Research and analysis about microstrip antenna for wideband and circular polarization technology have been conducted based on the previous studies. Several broadband circularly polarized microstrip antenna structures were designed for BGAN portable mobile terminal with the method of combing theoretical calculations, numerical simulations and experimental verifications. The author’s main work is as follows:(1) It describes the performance parameters of microstrip antenna and the key technologies of microstrip antenna of realization broad bandwidth, circular polarization and link matching. It gives a systematic introduction to the principles of circularly polarized microstrip antennas and the ways to improve the performance of circular polarization.(2) It focuses on the electromagnetic numerical simulation algorithm-Finite Element Method and engineering optimization algorithm-Taguchi’s method. The optimal design of GPS microstrip antenna was achieved by combination of both the Ansoft HFSS software based on the finite element method and the Taguchi’s Method based on orthogonal experimental design.(3) An antenna structure for BGAN land-mobile Class-2 terminal was proposed based on the analysis and research of the single-fed circularly polarized microstrip antenna technology. The antenna was carried out by simulation and experimental validation. The measured results show that the antenna has good CP radiation characteristics with its VSWR less than 1.2 and Gain higher than 13dB over the INMARSAT working band. The measured results are in good agreement with the simulated ones. The antenna has many characteristics such as small size, light weight, compact structure, simple production and suitable for portability and mobility. It has a good prospect of application and extension.(4) An antenna structure for BGAN land-mobile Class-1 terminal was proposed based on the analysis and research of the dual-fed circularly polarized microstrip antenna technology. The antenna was carried out by simulation and experimental validation. The measured results show that the antenna has good characteristics with its VSWR less than 1.35, Gain higher than 14dB and 3dB wide angle axial ratio more than 40°over the INMARSAT working band. A good agreement between experiments and simulations is found The proposed antenna with wide bandwidth, high gain and wide-angle circular polarization characteristics can be high-quality, high efficiency to achieve signal transmission and reception during the working band. The designed antenna has been successfully applied to HNS9201 outdoor mobile terminal to verify the feasibility of the design. The proposed antenna has a low-cost, easy-fabrication, suitable for high-volume production, and etc. It provides a practical transceiver antenna for BGAN land mobile satellite communications terminals.(5) A wideband circularly polarized microstrip slot antenna for L-band satellite communications was proposed based on the technique for an array to generate circular polarization with several linearly polarized elements. The antenna was carried out by simulation and experimental validation. According to the simulations and measurements, the antenna has its gain to 8dB with bandwidth VSWR<1.5 and AR<3dB of 52% and 49%, respectively. The antenna has good circular polarization radiation characteristics. The designed antenna has a high practical value in addition to simple and compact structure, low price and wide bandwidth. It also applies to small low speed inmarsat terminals.更多还原