Design of reflection-type metasurface with phase discontinuities

Accurate artificial manipulation of electromagnetic wave propagation is needed in many practical applications, and traditional optical devices and artificial electromagnetic media adopt three dimensional structure. By adjusting the transmission path to accumulate phase differences, the propagation state of electromagnetic wave is controlled, which makes the regulating device difficult to achieve planarization and it is difficult to integrate with other components. Recently, a new methodology of controlling the propagation of electromagnetic wave has been proposed as metasurface with pahse discontinuities in infrared region by introducing abrupt phase change at the interface, which provides a new solution to the construction of planar lenses. In this paper Reflection-type metasurface based on phase discontinuities is used to realise electromagnetic wave anomalous reflection in microwave region, which is regulated the large angle incident electromagnetic wave, and thus the regulation of electromagnetic wave propagation by plane ultrathin structure is achieved. First, a miniaturized unit cell structure for introducing abrupt phase changes at the interface is proposed and the unit cell structure is designed to maximize the reflection efficiency. Then utilizing the abrupt phase changes, the desired abrupt phase changes of the cross-polarized component covering 0-2π. According to the modified formula to calculated the rotation angle to satisfied the linear phase gradient. The reflection-type metasurface with linear phase gradient is fabricated to manipulate the reflected EM wave. And finally realized control the direction of the reflected electromagnetic wave. The simulation results show that the anomalous reflection angle of the transmitted cross-polarization component agrees very well with the theoretical value.