偏置反射面天线的研究与设计-电子科学与技术专业论文.docxVIP

摘 要近年来，散射通信技术的飞速发展对天线的小型化、高效率等特性提出了更高的 要求。角分集技术是散射通信技术中抗多径衰落和天线小型化的一种主要方法，如何 利用偏置反射面天线实现角分集成为了一个极具实用意义的研究课题。本文基于偏置 反射面天线的理论基础，对一种双波束双极化偏置反射面天线实现角分集技术进行了 研究。本文主要内容概括如下：1. 偏置反射面天线的基本理论分析。首先分析了偏置反射面天线的几何参数和 推导方程。然后针对馈源以线极化照射偏置反射面时交叉极化下降的问题，分析并使 用了大焦径比的优化方法。最后研究了馈源横向偏焦时波束偏移因子与焦径比的关 系。2. 馈源与正交模耦合器的设计。针对双波束双极化偏置反射面天线的双波束较 难实现小夹角的问题，依据馈源横向偏焦理论，首先采用了一种适于多波束天线的介 质棒辐射体馈源，然后为了使双馈源系统的两组馈源只产生最小的横向偏焦，设计了 一种插针型正交模耦合器，从而可以实现双馈源系统最小间距。最后将介质棒辐射体 与正交模耦合器组合，仿真和实测结果表明在工作频带内方向图与仿真结果基本相 符，耦合器的端口隔离度和驻波达到良好性能。3. 双波束双极化偏置反射面天线整体的研究与设计。为了完成馈源系统和偏置 反射面的设计，首先对馈源系统的其他器件，即功分器、扭波导、90°拐角等研究与 设计，将每个器件驻波优化到 1.1 左右后组合整个馈源系统，然后分析了双介质棒辐 射体相互耦合对方向图的影响，根据辐射体方向图设计偏置反射面，并对整体天线仿 真优化。最后从焦径比、双馈源系统间距、辐射体倾角三个方面分析了双波束小角度 的实现方法，最终完成了整体天线的设计并实现了良好的天线性能。关键词 ：散射通信；双波束双极化；正交模耦合器；偏置反射面AbstractHigher requirements for scatter communication are put forward in recent years, such as antenna miniaturization and high efficiency. Angle diversity is a main method to achieve multipath anti-fading and antenna miniaturization of scatter communication. How to implement angle diversity in offset reflector antenna shows great significance. A dual-beam and dual-polarization offset reflector antenna based on offset reflector antenna research status is proposed in this paper, which is a use of angle diversity technology application.The summary is proposed as follows:The theory of the offset reflector antenna is analyzed. At first, the geometric parameters and equations of offset reflector antenna is analysed. Then the large focal diameter ratio is studied and used to optimize cross polarization when the linear polarization is used of feed. Finally the relationship between beam deviation factor and focal diameter ratio is analyzed when feed lateral offset-focus.The design of feed and orth-mode transducer. To achieve a small angle relationship of the dual-beam and dual-polarization offset reflector antenna, a dielectric rod radiator is used and a pin ortho-mode transducer(OMT) which can achieve the minimum distance of two feed systems is