Research On Radar Cross Section Reduction Based On Reflective Metasurface

The rapid development of electronic technology and information technology has made the electromagnetic environment of the battlefield increasingly complex,thus traditional stealth technology cannot meet the needs of modern warfare.Metasurface is two-dimensional electromagnetic metamaterial,research on it is a hot spot at the moment.By changing the unit structure and arrangement of metasurface,it is possible to achieve flexible control of the characteristics of electromagnetic wave amplitude,phase,propagation mode and polarization form.The use of metasurface to reduce radar cross section and realize electromagnetic stealth has high application value.This new stealth method can meet the urgent needs of the stealth field for broadband,light weight and high efficiency.In this paper,based on the principle of phase metasurface,two encoding metasurfaces that can reduce radar cross section efficiently in a wide frequency range are designed for different occasions,then the influence of metallic mesh instead of continuous metal on metasurface is simulated.The specific content is as follows:1.Design metasurface unit structure with highly symmetrical metal pattern layer,phase response of the metasurface unit is not sensitive to the polarization angle of the incident wave.Design a phase gradient metasurface based on the generalized Snell's law to realize the abnormal reflection of reflected electromagnetic waves in two-dimensional plane and three-dimensional space.Based on the array theory,the genetic algorithm is used to optimize the arrangement of metasurface elements to obtain a 1-bit encoded metasurface.The metasurface can efficiently reduce the radar cross section in a wide frequency range and has a certain degree of incidence angle insensitivity.2.Design two broadband high-efficiency polarization conversion units that are mirror images of each other based on the polarization conversion principle,the two units can have a high polarization conversion rate in a wide frequency range,and the higher the polarization conversion rate of the two units,the closer the phase difference is to 180°.By optimizing the arrangement of metasurface units based on the array theory,a 1-bit encoded metasurface with high polarization conversion rate and high efficiency reduction of radar cross section in a wide frequency range can be obtained.3.The continuous metal pattern layer and the metal back plate of the metasurface are replaced with visible-infrared transparent metallic mesh,and the medium of the intermediate layer is selected as a light-transmitting medium,which can make the metasurface transparent to the optical band.The simulation analyzes the effect of replacing continuous metal with metallic mesh on the performance of metasurface,and designs two optically transparent coding metasurface units.By optimizing the arrangement of the two units,an optically transparent coding metasurface that reduces radar cross section in a wide frequency range can be achieved.