天线测量中的近远场变换程序设计和测试

论文总字数：33247字

摘 要

天线远场测量是可以直接测量天线辐射特性的方法，因此具有很强的通用性，但测试距离必须满足远场条件。随着各种通信技术和雷达技术的发展，天线口径尺寸不断增大，远场条件往往无法满足或者需要很长的测试距离。当长距离测量时，由于缺少理想屏蔽吸波条件，测量容易受到环境因素影响。另一方面，随着新型具有涡旋波束的天线出现，已无法单独通过远场测量方法来进行全部辐射性能的测量。上述因素极大的促进了近场测量技术的发展和普及。与远场测量方法相比，近场测量受场地的限制小，受空间电磁环境影响小。在采用适当的方法并能通过补偿修正误差的时，近场测量的测量精度可以达到甚至超过远场测量的精度。

本毕设针对天线近场测量方法，开展相关的方法学习和研究，以及编制相关近远场变换的数据处理软件。主要内容包括：（1）学习并掌握天线近场测量方法中坐标系的变换、平面近场测量的基本原理，理解平面波展开方法，平面近场测量中的采样参数确定等，并基于MATLAB 编写天线近场测量数据后处理软件实现近远场变换，并通过仿真和实测方式进行验证。（2）学习并掌握天线近场测量方法中柱面近场测量的基本原理，理解柱面波展开方法，柱面测量中的探头性能补偿等，并基于MATLAB 编写天线近场测量数据后处理软件实现近远场变换，并通过仿真天和实测方式进行验证。（3）进一步，还将进行相关测量误差分析，和实际测量系统比较分析，证实了采样点数、远场坐标参数精度的取值会对计算结果的产生影响。

本毕设最终完成了平面近场和柱面近场的近远场变换程序，其中平面近场程序具有良好的准确性，和仿真结果相比在主瓣方向吻合一致，和实验结果相比吻合情况也较为良好。柱面近场程序也完成，通过实验对比，可以获得较好结果。

关键词：近远场变换、天线平面近场测试、天线柱面近场测试

ABSRTRACT

The far-field measurement method of antennas is a method that can directly measure the radiation characteristics of antennas, so it has strong versatility, of which the test distance must satisfy the far-field conditions. With the development of wireless communication technology and radar technology, the aperture sizes of corresponding antennas are increasing drastically, and the far-field conditions are often unable to meet or a long test distance is required. When long-distance measurement is carried out, the measurement is easily affected by environmental factors due to the lack of ideal shielding and absorbing conditions. On the other hand, with the emergence of a new type of antenna with a vortex beam, it is impossible to measure all the radiation performance through far-field measurement only. These factors have greatly promoted the development and popularization of near-field measurement technology. Compared with far-field measurement, near-field measurement is less limited by site and less affected by space electromagnetic environment. When appropriate methods are adopted to compensate errors in measurements, the accuracy of near-field measurement can reach or even exceed that of far-field measurement.

The thesis includes the studies and learning progress of the near-field measurement method of antennas, and programs as well as compiles measured data processing software for near-field to far-field transformation. The main contents are as follow: (1) Learning and mastering the basic principles of coordinate transformation and planar near-field measurement of antennas, understanding plane wave expansion method, determination of sampling parameters in planar near-field measurement, etc., and compiling the post-processing software of antenna near-field measurement data based on MATLAB to realize near-field to far-field transformation, and verifying the program using simulation case and measurement case. (2) Learning and mastering the basic principle of cylindrical near-field measurement, understanding cylindrical wave deployment method and probe performance compensation in cylindrical measurement, and programming the post-processing software of antenna near-field measurement data based on MATLAB to realize near-field to far-field transformation, and verifying it by simulation case and measurement case. (3) In addition, the relative measurement error analysis are carried out and compared with the actual measurement system. It is confirmed that the sampling points and the accuracy of far-field coordinate parameters will affect the calculation results.

In the end, the near-field to far-field conversion program of plane and cylindrical near-field is completed. The plane near-field measurement program has good accuracy, which is consistent with the simulation results in the main lobe direction and the experimental results are in good agreement. The cylindrical near-field program is also completed, and good results can be obtained through experimental comparison.

Keywords: near field to far field transformation, planar near-field measurement, cylindrical near-field measurement

目 录

摘 要 I

ABSRTRACT II

第一章 绪论 1

1.1 天线近远场测量的发展历史和现状 1

1.2本文研究重要的内容和重点 3

第二章 平面近场测量基本原理 5

2.1 平面波谱展开原理 5

2.2 平面近场测量的基本原理 7

2.3 平面近远场变换算法 8

2.4 小结 10

第三章 柱面近场测量基本原理 11

3.1柱面波展开 11

3.2从探头补偿近场测量确定远场 13

第四章 近远场变换实验仿真 19

4.1 平面近场测量仿真程序 19

4.2 柱面近场测量仿真程序 35

4.3 小结 40

总 结 41

参考文献 42

致 谢 43

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