摘要随着无线电技术应用领域的不断扩展，天线已经越来越多地被装载于各种体积小、移动快的载体之上，因而在天线的设计上有它特殊的要求：重量轻，体积小，易于共形且不能影响载体的运动。因此，纳米级材料制作天线的应用发展前景越来越广泛。61670

本文首先对传统八木天线的基本理论做了简单的介绍，进而将其延伸至纳米天线领域。再从获取较高增益和较好方向性并且结构简洁易实现的角度出发，参考外文文献的纳米八木羽田天线设计范例，使用Ansoft HFSS软件进行纳米八木天线的仿真设计，并分析该天线模型的各主要参数与性质，然后对设计过程中遇到的各种问题做出了讨论和分析。

在此基础上，本文又有针对性地改进了天线的参数与结构，以达到提高方向性、增益，减小误差的目的。然而，这种改进一部分是建立在理想情况的基础上，其中若干设计条件是现今纳米技术难以达到的，在实际生产中，还需要等待纳米材料制作工艺技术的提高以及其成本的降低。

毕业论文关键词:纳米 八木天线 HFSS 仿真 方向性 增益 极化方式 改进

Title    The design and simulation of nano Yagi-Uda antennas

Abstract As the widespread and development of radio technology application, antennas are more and more frequently applied in various of carriers which have smaller sizes while need to move at a high speed . Therefore, some new and special requirements, such as being light in weight, being compact in size, being easy to be conformed and being limited influence on carriers movement, appeared during designing the up-to-date antennas. As a result, the application of nano materials in manufacturing antennas has a positive prospect predictably.

In this paper, what is introduced firstly and concisely is The principle of the original Yagi antenna. Then, it goes into the field of nano antennas. After that, in terms of obtaining a high gain and a demanding directivity with a compact structure, a model of nano Yagi antenna is designed and simulated, using the software named Ansoft HFSS, with referring to some other literatures. Moreover, to discuss and solve the problems that come up when designing the model, the main parameters and properties are analysed with the help of HFSS.

Based on that, the parameters and structure of the model is improved accordingly in the 4th part of the paper, purposed to improve the directivity and gain efficiently and to obtain an error reduction. However, some of the conditions are based on the ideal world, which is hardly satisfied by current nano technology and have to wait for the development of the nano technology to realize it practically.

Key words: nanometer   Yagi-Uda antenna   HFSS   simulation   direction   gain   polarization   improvement

1  绪论…  1

1.1  天线概述  1

1.2  纳米天线  1

1.3  八木天线  2

2  天线的基本理论  3

2.1  天线的发展和应用概况  3

2.2  天线的基本原理…  4

2.3  天线的主要参数与性质  4

2.4  现代仿真技术在天线设计中的应用…  7

3  纳米八木天线的分析设计  9

3.1  八木天线的工作原理…  9

3.2  八木天线的模型设计…  9

3.3  纳米八木天线的HFSS仿真模拟结果… 13

3.4  误差分析  18

4  基于纳米八木天线模型的改进  20

4.1  模型结构的优化…  20

4.2  尺寸参数的优化…  20

4.3  改进后模型的仿真建立  20