Design And Research Of Quad-frequency Artificial Electromagnetic Metasurface

Metamaterial is a new type of artificial material which size is much smaller than the working wavelength.The physical properties of metamaterial do not depend on the parameters of the material,but on the artificially designed structure.When metamaterials interact with electromagnetic waves,they can produce some unique physical phenomena that cannot be produced by natural materials.Metasurface is the two-dimensional version of metamaterials,which has the same electromagnetic properties as metamaterials.Compared with three-dimensional bulk metamaterials,the metasurface is an ultra-thin material.Metasurface makes up for the disadvantages of large volume and unfavorable integration of metamaterial,therefore it has been widely studied.With the quickly development of integrated systems,the research on metasurfaces not only stops at the realization of a single frequency and function,but also extends to the use of simple structures that can simultaneously realize multi-frequency and multi-function.In this paper,we mainly study multi-frequency metasurface.By analyzing the principle of the Pancharatnam-Berry phase metasurface,we proposed two quad-frequency metasurfaces.The main work of this paper are as follows:1.A quad-frequency transmissive metasurface with independent phase modulations is designed,and the transmission amplitude is about 0.45.Four different functions are designed under quad-frequencies,including: single converged vortex beam generator,double converged vortex beam generator,meta-hologram and focusing lens.The designed metasurface array was verified through full-wave simulation and experiment,the test results are in good agreement with the simulation results.The results verify the ability of the designed transmissive metasurface array to control electromagnetic waves.2.A quad-frequency reflective metasurfaces with independent phase modulations is designed,and the reflection amplitude is about 0.85.Compared with transmissive metasurfaces,the reflective metasurfaces have higher amplitude.Based on this unit,one-dimensional beam deflection array and one-dimensional focusing lens array are designed to verify the performance of the metasurface unit.Then design a two-dimensional converged vortex beam generator which can generate vortex beams with different number of modes at four frequencies.The designed metasurface array is verified through theoretical calculation and full-wave simulation,the simulation results are in good agreement with the preset results.The quad-frequency metasurface that designed in this article is of key significance for the expansion of channel bandwidth and capacity of communication systems.