摘要:星载赋性的反射面天线在机载通信和广播卫星当中的应用越来越广泛。这些星载赋形的反射面天线有效的覆盖了地面上的不规则区域,并最小化了对范围之外区域的干扰。其在覆盖较大面积时具有高增益,并具有使通信卫星多频次复用,有效利用频谱资源等优点,受到世界各国广泛重视。
在本文里,在下对星载反射面天线的精确馈源位置以及其赋形技术进行了比较深入的讨论和研究。本论文工作的主要工作可以概括如下:
第一,介绍了Zernike多项式展开法将反射面表面参数化表示的方法。并讨论了单偏置反射面天线的Zernike展开系数对反射面形状和远场辐射方向图的影响。
第二,介绍了赋形区域采点方法和适应值函数的选取方法。然后,介绍了高斯扰动蝙蝠算法的基本原理。并结合上述方法,研究了波束赋形的反射面天线的设计流程。
第三,为了验证高斯扰动蝙蝠算法的高效性与有效性,我们使用单馈源单偏置反射面天线及多馈源单偏置反射面天线实现中国国土区域的赋形。
关键词:赋形反射面,适应值函数,Zernike多项式,蝙蝠算法
Abstract:Offset Reflector Antenna are increasingly used on-board communication and broadcast satellites to achieve efficient coverage of irregularly shaped regions on earth and to minimise interference outside the coverage boundaries.
In this paper, the precise feed positions and shaping techniques of single offset reflector antennas are well studied. The major works of this thesis can be summarized as follows:
Firstly, the method of the reflector parameterized by Zernike polynomial expansion is introduced. And the sensitivity of the reflector shape and the far-field radiation pattern to the variation of the Zernike polynomial expansion coefficients are studied for the single offset reflector antennas.
Secondly, the methods of choosing sampling points and selecting fitness function are introduced. the basic principle of Gaussian bat algorithm (GBA) is introduced. With these methods, the design flow of contoured reflector beam antennas is studied.
Last, several different examples verify the validity of the beam forming method. A contoured beam covering the China’s territory region with the desired directivity is obtained by shaping the single offset reflector antennas.
Keywords: Shaped reflector, Optimization algorithm,Zernike,Bat algorithm
目录
摘 要 3
Abstract 4
目 录 5
1绪论 7
1.1研究背景及意义 7
1.3本文的主要内容及文章结构 9
2反射面天线性能分析的基本理论 10
2.1单偏置反射面天线的几何结构 10
2.2单反射面天线分析中的坐标转换 11
2.2.1远场平面和天线坐标系的转换 11
2.2.2直角坐标系与球坐标系的转换关系 12
2.2.3不同直角坐标系的转换 14
2.3反射面天线的馈源 16
2.3.1理想高斯馈源的表达式 16
2.3.2理想高斯馈源的方向图 18
2.4反射面天线辐射场计算方法