基于六边形P-B相位单元超表面的毫米波涡旋波束发生器

Generation of millimeter-wave vortex beam besed on hexagonal P-B phase meta-atom metasurface

为了产生高纯度的毫米波涡旋波束,提出了一种基于Pancharatnam-Berry(P-B)相位原理的反射型宽带六边形单元结构。该超表面单元由表层变形的Minkowski分形结构贴片、中间F4B介质层和金属地板组成。在涡旋波束的螺旋相位中引入馈源补偿相位,利用此单元分别设计了34 GHz处l=1的六边形和方形排列的超表面。对比仿真电场和OAM光谱分析结果可知,采用六边形排列的超表面产生的涡旋光束模式纯度为0.94,相比较于方形排列的0.86提升了0.08(9%)。另外,对26~43 GHz宽带范围内l=1,2,3的超表面进行设计仿真,得到三个模式下的涡旋波束纯度分别可达0.94,0.87,0.77。仿真结果表明,所设计的六边形单元排列超表面能够有效地产生高纯度的涡旋波束。

To generate high-purity millimeter-wave vortex beams,a reflective broadband hexagonal meta-atom structure based on the pancharatnam-berry(P-B)phase principle was proposed.The meta-atom consisted of a surface-deformed Minkowski fractal structure patch,a middle F4B medium layer and a metal floor.By introducing the feed compensation phase into the helical phase of the vortex beam,the hexagonal and square metasurfaces with l=1 were designed at 34 GHz using this meta-atom.According to the simulated electric field and OAM spectral analysis results,the vortex beam purity produced by the hexagonal arrangement metasurface is 0.94,which is 0.08(9%)higher than that of the square arrangement(0.86).In addition,the metasurfaces with l=1,2,3 in the broadband range of 26-43 GHz were designed and simulated.The vortex beam purities of 0.94,0.87,and 0.77 were achieved for the three modes.The simulation results show that the designed metasurface with hexagonal meta-atom arrangement can effectively generate high-purity vortex beams.