Research And Design Of Beam-steering Antenna Based On Metasurface

With the rapid development of satellite communication technology,the low-orbit satellite communication networks are deeply integrated with the terrestrial wireless network5G or 6G to solve the problems of small signal coverage and weak signal in some areas.Low-complexity and easy to deployment of multi-beam or beam-scanning antennas play an important role in the integration of space,space and earth communication systems.This paper is based on the special reflection/refraction principle of metasurface to electromagnetic wave and the resonant cavity theory the electromagnetic wave beam radiated by planar microstrip antenna is flexibly regulated,and the metasurface antenna is studied for the purpose of realizing multi-beam radiation and beam scanning functions.The main work of this paper is as follows:1.Design of multi-beam switching antenna loaded square structure metasurface.The special electromagnetic transmission characteristics of square patch metasurface loaded with metal probes were studied,and the metasurface antenna working in the Ku band were designed by combining metasurface with microstrip antenna by using their characterstics.The simulation and experimental results show that the metasurface antenna achieves large Angle beams deflection with four different directions in the pitch plane by excitation of four feeding input ports respectively.Four beam deflection Angle are respectively（φ,θ）=（0°,52°）,（90°,52°）,（180°,52°）,（270°,52°）and gains are 10.4d B.The metasurface antenna has profile height of only0.2λ₀.2.Design of multibeam switching antenna based on defective metasurface.The refraction characteristic of defect metasurface to electromagnetic wave is analyzed and used,and the slot antenna was placed below the defective metasurface as a radiation feed and it’s placed 0.13λ₀ below the defective metasurface as radiative antenna.The four input ports of the fed antenna are excited respectively.And the metasurface antenna radiates four beams of different directions at 6.76GHz.Four beam deflection Angle are respectively（φ,θ）=（0°,35°）,（90°,35°）,（180°,35°）,（270°,35°）and gains are 9.12 d B.3.Design of low-cost,high-gain multi-beam radiating and beam scanning antenna.The PIN diode is loaded on the metasurface unit based on the digital metasurface coding principle and"1"bit phase control unit is designed This unit is used to form 5x5 metasurface,the metasurface is coded and controlled by"MCU"so as to realize flexible regulation of electromagnetic beam.The switching state of each unit on the metasurface was controlled independently by controlling board of MCU.Thus,the metasurface phase distribution can be controlled in real time.The simulation and experimental results show that the programmable metasurface antenna realizes multi-beam flexible switching and beam-scanning functions of 9.44-9.72GHz.To further improve the radiant beam gain,a planar lens with high transmittance is designed.After loading the lens,the single-beam gain is improved by"4dB".