Research On Beam Reconfigurable Antenna Technology Based On Metasurface

Antenna is the final device at the transmitting end and the first device at the receiving end in wireless communication system,and is also an energy converter between the guided wave and the electromagnetic wave in space.The development of wireless communication systems such as mobile communication,satellite communication,and radio frequency identification technology relies on antennas,and also proposes new higher requirements on antennas.Reconfigurable antenna technology reconstruct the important parameters of the antenna by reasonably designing antenna.It plays a vital role in reducing the complexity and the cost of the communication system.As a kind of two-dimensional artificial electromagnetic material,metasurface consists of a series of sub-wavelength unit cells,which can easily regulate the electromagnetic wave radiation characteristics.Designing antennas by using metasurface can simplify the antenna structure and reduce the antenna profile.Metasurface has an important and wide application in reconfigurable antenna technology.This paper mainly studies the beam reconfigurable antenna based on metasurface.The main research contents and innovations are as follows:1)One-dimensional array beam reconfigurable antenna operating at 915MHz is designed by using the unit phase control method.The unit is fabricated using substrate integrated waveguide technology.PIN diode is used to control the phase of each unit and PIN diode bias circuit for regulating radiation units is designed.The designed antenna has been fabricated and tested.A preliminary exploration of the beam reconfigurable antenna based on metasurface is carried out.2)Using liquid crystal material and microwave holography technology,a beam reconfigurable antenna based on metasurface is designed to radiate a beam in any spatial direction above the plane.The antenna works at 39 GHz.The two-dimensional metasurface is composed of a plurality of liquid crystal cells.Control the liquid crystal dielectric constant by changing the bias voltage on each liquid crystal cell,so that the dielectric constant of the liquid crystal cells at each position is regularly distributed,and the beam radiation direction of the source antenna is controlled.3)The solution about the problem of lobe sag of the above-mentioned beam reconfigurable antenna based on liquid crystal metasurface has been achieved.The influence of the number of liquid crystal metasurface unit cells on the beam radiation direction regulation is studied.The liquid crystal metasurface is digitally encoded to achieve digital control of the beam radiation direction.