摘要对于大部分的现代通信系统，上行和下行部分都是工作在不同频率上的，如果使用 双频带天线，其体积和资金花费将大大减小。而在很多设计应用中，使用圆极化方式可 以减小系统对天线朝向的敏感性，故圆极化天线是较为推荐的选择。同时，微带天线以 其体积小、重量轻的特点，也得到了广泛的应用。78933

本文结合微带天线基本理论和国内外文献资料，研究双频双圆极化微带天线。采用 双工器连接两个不同频率、不同圆极化方式的独立贴片，来实现双频圆极化微带天设计。 首先设计出一种 2。4GHz/3。4GHz 的双频双圆极化天线，两频率下阻抗匹配和圆极化性能 良好。然后根据天线最佳布阵间距和不同频率比下天线的设计实验，对该方案能够实现 的双频频率比进行分析。最后针对某工程项目 8。2GHz /8。6GHz 双圆极化的要求，提出独 立馈线加入带通滤波器的结构，实现了在低频率比下双频圆极化微带天线的设计。

毕业论文关键词 双频圆极化 微带天线双工器

毕 业设计 说明书 外文摘 要

Title Design of Dual-Band Circularly Polarized Microstrip Antenna

Abstract In most modern wireless communication systems, the uplink and downlink are operating at different frequencies。 The cost and volume can be reduced greatly if dual-band antennas are used。 Circularly-polarized antennas are recommended in many applications due to their insensitivity to the antenna orientation。 Meanwhile, microstrip antennas are widely used due to their advantages of small size and light weight。

In this thesis, the design on dual-band, dual circularly-polarized (CP) microstrip antennas is investigated based on the study of basic theories and the literatures at home and abroad of microstrip antennas。 Two independent patches, operating at different frequencies and with different rotation senses of CP, are integrated together by a diplexer to achieve the dual-band, dual circularly-polarized design。 First, a dual CP antenna is designed at 2。4GHz/3。4GHz with good impedance matching and CP performance。 Then, the achievable ratios of two operating frequencies are analyzed based on the element-spacing requirement for constituting an array and simulated study on antennas with different frequency-ratios。 Finally, a novel dual CP antenna operating at 8。2 GHz /8。6GHz is proposed for a specific project, in which two band-pass filters are introduced in the independent feed-lines to achieve dual CP radiation at dual band with the very low frequency ratio。

Keywords  dual-band circularly  microstrip antenna  diplexer

本科毕业设计说明书 第 I  页

目 次

1 绪论 1

1。1 研究背景 1

1。2 国内外研究情况 1

1。3 内容安排 2

2 圆极化微带天线设计 4

2。1 微带天线的定义和结构 4

2。2 微带天线的工作原理 4

2。3 微带天线的圆极化技术 6

2。4 2。4GHz微带圆极化天线设计