基于超材料的TEM-TE11高功率微波模式转换器

A metallic metamaterial high power microwave mode converter

利用高功率容量高折射率的超材料作为移相介质,设计了一种高功率微波TEM-TE11模式转换器。采用扇形金属栅格作为材料阵元,通过对阵元的角向及轴向的周期排布得到高折射率超材料并将其填充在模式变换区角向半空间内。TEM模微波在通过模式转换区域之后,超材料填充区域电场与未填充材料的真空区域电场相位差达到180°,从而实现TEM模到TE11模的模式转换。采用CST Microwave Studio软件对模式转换器进行了数值模拟,结果显示该转换器在工作频点附近具有较高的转换效率,相对带宽约4%。结合模式变换器开展了辐射天线的设计,模拟得到典型的TE11模远场方向图。

A metallic metamaterial high power microwave(HPM) mode converter which converts cylindrical TEM mode to TE11 mode is presented. Metallic sector grid elements are periodically arranged both in the azimuthally and longitudinal direction to gain high refractive index. High refractive index metamaterial fills half space of the cylindrical transmission line of the mode converter in the azimuthally direction. The phase of electric field was shifted from 0 degree to 180 degrees between the metamaterial part and the vacuum part as the microwave propagates though the mode converter, hence the microwave mode is converted from TEM mode to TE11 mode. The mode converter is simulated by 3D commercial electromagnetic simulation software CST Microwave Studio. Simulation results show that the converter has high convert efficiency with bandwidth of about 4%. Radiation antenna with metamaterial mode converter is simulated. The radiation pattern reveals a typical TE11 mode pattern which validates the design of mode converter.