| Metasurfaces are two-dimensional extensions of metamaterials,which have advantages of lower profile,thinner thickness,more flexible unit design,and easier processing than metamaterials.It can flexibly and effectively manipulate the amplitude,phase,polarization and propagation modes of electromagnetic waves.The main contents and innovations of this article are as follows:Firstly,we propose a metasurface to realize a high-gain horn antenna.In order to solve the large volume and bulky structure of traditional high-gain horn antennas,we propose an ultra-thin metasurface.By loading the metasurface on the horn aperture,the spherical wave inside the horn is converted into a plane wave,which increases the gain of the antenna.Simulation and experimental results show that when the center frequency is 12.5 GHz,the peak gain of the antenna can reach 24.2 dBi,and when the center frequency is 30 GHz,the peak gain of the antenna can reach 28.9 dBi.Then,we propose a metasurface to generate vortex beams.In order to solve the huge system of optical vortex generator systems and complex structures of metamaterials,we propose a low-profile metasurface,which consists of a split ring unit.The unit can achieve eight-phase distribution in a 360 ° range with high efficiency and realize the 90° polarization rotation.By designing the metasurface,the generation of traditional vortex waves,non-diffraction Bessel vortex waves and double-mode vortex beams are achieved.In the end,we propose a metasurface to generate Airy beams in the microwave field for the first time,which is composed of a double-split ring unit.By adjusting the geometry and rotation angle of the split ring,the amplitude and phase of the incident wave can be controlled.This unit can achieve eight-phase distribution in a 360° range,and the transmission efficiency control from 0-1.Through the design of the metasurface,the generation of Airy beams and self-focusing Airy beams are realized. |
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