Fig. 1. The structute of the metagrating: (a) The schematic of the retroreflection metagrating, wherein red and green arrows indicate retroreflection and blue arrows indicate specular reflection; (b) the diagram of metagrating with two sub-cells; (c) the iso-frequency contours of the incident wave and reflection wave for the metagrating.超构光栅的结构示意图　(a)逆向反射超构光栅的示意图, 其中红色和绿色箭头均表示回射, 蓝色箭头表示镜面反射; (b)超构光栅的结构单元示意图; (c)超构光栅入射和反射的等频图

Fig. 2. The reflection efficiency of different orders and the total magnetic field pattern, while the designed retroreflection angle is : (a) The reflection efficiency of different orders vary with incident angle; (b) the total magnetic field pattern of the two-channel retroreflector. 设计的回射角为 时, 超构光栅的不同级次的反射效率以及高斯波入射到超构光栅的总磁场图　(a)超构光栅不同级次的反射效率随入射角度变化曲线; (b)高斯波入射到超构光栅, 双通道回射的总磁场图

Fig. 3. The reflection efficiency of different orders and the total magnetic field pattern, while the designed retroreflection angle is : (a) The reflection efficiency of different orders vary with incident angle; (b) the total magnetic field pattern of the two-channel retroreflector. 设计的回射角为 时, 超构光栅的不同级次的反射效率以及高斯波入射到超构光栅的总磁场图　(a)超构光栅不同级次的反射效率随入射角度变化曲线; (b)高斯波入射到超构光栅, 双通道回射的总磁场图

Fig. 4. The incident angle of retroreflection and retroreflectivity corresponding to different period lengths . With the change of , the duty cycle and filling medium of the metal slot remain unchanged. 逆向反射的效率和工作角度随周期长度的变化规律. 随 改变过程中, 金属槽的占空比和填充介质保持不变