中文摘要：

在介质基板刻蚀的金属线和金属化过孔组成双U形结构模型，仿真计算及电磁参数反演结果表明，当电磁波垂直入射时，该结构在频率f=7．63GHz附近等效介电常数和等效磁导率实部同时接近零，从而得到了折射率为零的超材料，实验测试与仿真结果基本一致．同时，为了实现对零折射率响应频点的调节，分析了单元结构的金属过孔间距及U形结构脚长的变化对零折射率特性的影响，发现改变单元结构参数可改变零折射率响应频点．这种可调双u形零折射率超材料单元结构简单，可应用于微波器件等领域．

英文摘要：

A structure of zero-index metamaterial composed of two anti-symmetrical U-shaped metal via holes and strip wires is proposed.The retrieved results indicate that the effective permittivity and per- meability of the proposed structure is close to 0 at the frequency of 7.63 GHz when normal linearly polar- ized wave is incident directly, and the experimental results coincide with the simulation results.At the same time,by changing the via holes spacing and the feet length of U-shaped metal, we analyze the characteris- tics of the zero refractive index to study the adjustment of the frequency responses of zero refractive index point.We find that the response frequency of the zero refractive index will be changed by adjusting the geo- metric parameters of unit cell.The adjustable U-shaped zero-index material is simple and can be easily fab- ricated which can be utilized conveniently in the fields of microwave devices.