大连海事大学通信工程专业毕业论文.docVIP

大连海事大学 毕 业 论 文 二○一三年六月 圆形微带天线的仿真设计 专业班级：通信工程1班 姓 名： 指导教师： 信息科学技术学院摘 要 微带天线以其体积小、重量轻且容易实现多频段的特点，越来越得到广泛应用，但其带宽较窄，限制了其发展，因此展宽微带天线的带宽具有十分重要的意义。 为了拓宽阻抗带宽，本文通过HFSS仿真软件，对圆形微带天线进行建模研究。天线采用聚四氟乙烯和空气两层介质，通过同轴探针顶部加载圆形金属电容片来对辐射贴片进行耦合馈电，由此补偿探针引起的电感，调整圆形贴片尺寸、金属电容片尺寸和馈电点位置，来达到谐振点。并且分析了不同厚度空气层介质对微带天线带宽的影响，分析其规律，最终使天线带宽达到最大。本文中建模仿真的工作频率为2.45GHz，分析结果表明最终得到带宽达到24%，远超过一般微带天线的2%-5%。 关键字：宽频带；圆形微带天线；电容馈电 ABSTRACT Microstrip antenna is getting widely used because of the characteristics of small volume, light weight, and easily achieving multi-band operation. But the narrow bandwidth totally limited its development, improving the bandwidth of the microstrip antenna has much vital significance. In order to broaden the impedance bandwidth, a study on the circular microstrip antenna based on the HFSS simulation software is performed in this paper. The antenna consists of two layer medium, which are the PTFE and the air, feeding the radiation patch by adding a circular metal capactive patch to the top of coaxial probe, so this could cancel out the inductance caused by probe. By adjusting the size of the radiation patch and capacitive patch, and the position of the feed point, the resonance point can be achieved. The analysis of the effect of different thickness of the air layer on the bandwidth of microstrip antenna is performed to find the maximum bandwidth. The operation frequency of the designed antenna in this paper is 2.45GHz, the results show that the bandwidth of 24%, far more than 5% of the traditional microstrip antenna. Keywords：Broadband; Circular microstrip antenna; Capactive fed 目录 1章 绪论 1 1.1 概述 1 1.1.1国内外研究动态 2 1.1.2.研究目的和意义 2 1.2 本章小结 2 第2章 微带天线的基本理论 3 2.1 概述 3 2.2 微带天线的分析方法 3 2.2.1 传输线法 4 2.2.2 空腔模型 5 2.2.3 其它方法 6 2.3 微带天线的馈电方法 6 2.3.1 微带线馈电 6 2.3.2 同轴线馈电 6 2.3.3 电磁耦合馈电 7 2.4微带天线频带展宽的方法 7 2.4.1采用厚基板 7 2.4.2采用相对介电常数较小或损耗角正切较大的基板 7 2.4.3附加阻抗匹配网络 8 2.4.4采用楔形或阶梯形签板 8 2.4.5采用非线性基板材料 8 2.4.6采用非线性调整元件 8 2.4.7采用在贴片或接地板 “开窗”的办法 9 2.5空气介质对天线影响 9 2.6 本章小