基于分形的特异媒质层设计及应用于提高天线增益

Design of metamaterial layer based on fractal geometry for increase of antenna gain

根据分形原理,设计了一种新颖的分形图案。通过在印刷板(PCB)上周期性地蚀刻该分形图案制作了一种微带结构的特异媒质层。仿真计算表明,随着一些分形结构参数变化,该特异媒质层对电磁波具有连续变化的反射系数幅度和相位。依据部分反射层理论,将该特异媒质层加载在矩形贴片天线前方,在天线的工作频点、带宽和定向辐射特性基本保持不变条件下,矩形贴片增益得到不同程度提高。加工制作了特异媒质层和矩形贴片天线,测试结果验证了设计和仿真计算的正确性。

A new fractal pattern was designed according to the fractal principle. A microstrip metamaterial layer was made by periodically etching this pattern on a PCB（printed circuit board）. The simulation calculation results indicate that metamaterial layer possesses an encouraging feature,i.e. the amplitude and phases of its reflection coefficient can vary continuously with its structural parameters. According to the partial reflecting layer principle,this metamaterial layer is placed in front of a rectangular patch antenna. In this way,various degree of gain improvement can be achieved while the antenna′s working frequency,band-width and directional radiation property remain unchanged. The metamaterial layer and the rectangular patch antenna are fabri-cated and measured. The measured result validated the correctness of the simulation and calculation.