基于分形单元的微带反射阵列天线设计

Design of microstrip reflectarray antenna based on fractal element

分形呈现了自相似的图案，已被广泛应用于天线设计，以实现小型化和多频带。分形反射单元的提出，提供了一个在相位范围内更平滑的反射相位曲线。由于分形几何的空间填充性，反射阵面可以包括反射单元的种类较多。采用L系统法设计了一种“万”字形分形结构的微带反射单元，反射面的物理口径为300min×300mm，反射单元规模为13×13。仿真和测试表明，在5．8GHz处，天线的增益为22．6dBi，阻抗带宽为6．9％（从5．71～6．11GHz），印证了“万”字形分形结构设计反射单元的可行性，研究结果为设计反射单元提供了一种有效的新方法。

Since fractal can display self?similar pattern,it has been widely used in antenna design to achieve miniaturiza?tion and multiband. The proposed fractal reflection element offers a more smooth reflection phase curve in phase range. Due to fractal geometry has space?filling property,the reflectarray surface can include kinds of reflection elements. A novel antenna reflection element with“万”shape fractal structure was designed by using L system approach. The physical caliber of reflecting surface is 300 mm×300 mm,and the array scale of reflection element is 13×13. Simulation and test results show that the antenna gain is 22.6 dBi when the antenna works at 5.8 GHz,and the impedance bandwidth is 6.9% when the antenna works from 5.71 GHz to 6.11 GHz. It is proved that using“万”shape fractal structure to design reflection element is feasible. The research results provide a new effective method for designing reflectarray antenna.