Research On Pattern Reconfigurable Antenna Based On Liquid Metal

With the rapid development of modern wireless communication systems,especially in the age of 5G communication,the communication system tends to lower environmental interference,high-capacity information processing,high integration,and multiple working modes in transmit-receive.Reconfigurable technology can adjust the antenna geometry and current distribution through the mechanical drive,electronic switch,photoconductive switch,and other means to provide flexible and variable radiation characteristics,improve or eliminate the limitations of physical size and equipment deployment,and adapt to the changes of environmental conditions or system requirements.Among them,pattern reconfiguration technology can weaken noise sources and electromagnetic interference by providing better signal directivity from the base station to the required users to improve channel security and communication reliability.As an emerging metal material,gallium-based liquid metal has broad application space in reconfigurable electronic devices because of its good conductivity and low melting point.Therefore,this paper mainly carries out the technical research of pattern reconfigurable antenna based on gallium-based liquid metal,including the research of pattern reconfigurable theory,the characteristic analysis of liquid metal,the design of microfluidic channel and driving scheme.The main work is as follows:(1)A double-dipole antenna with a reconfigurable pattern based on liquid metal is proposed.Based on the W8JK double-dipole end-fire array model,the antenna utilizes liquid metal and microfluidic technology to add and reconstruct the second pair of radiation dipoles to the original metal dipole arms.The beam switching from broadside to unidirectional end-fire is realized by asymmetric path feeding to excite different phase differences.By mechanically changing the height of the antenna from the ground,the liquid metal double dipole achieves 20° to 50° deflection at 2.5GHz.Finally,based on the proposed antenna as array unit,an eight-element linear phased array is designed,and its beam scanning performance is tested.The results show that the array has lower sidelobe level and less than 3dB gain fluctuation in the liquid metal double-dipole mode compared with the traditional dipole array.(2)A Fabry-Perot resonator antenna with reconfigurable pattern based on liquid metal is proposed.Based on the Fabry-Perot cavity model,the antenna constructs the gradient phase distribution and realizes onedimensional beam deflection by adjusting the shape of C-shaped rings elements arranged on the partially reflective surface and introducing discontinuous transmission phase and amplitude.By analyzing the electromagnetic characteristics of the C-shaped rings at different opening angles and opening orientations,the design theory and reconfiguration implementation method of partial reflective surface are introduced in detail.Four metasurface layout projects for 5×5 array are proposed to realize highgain multi-angle deflection at 4.9 GHz.In addition,two drive projects,liquid metal infusion and mechanical drive,for 3×3 array are designed,and the prototypes show reliable beam switching ability.Finally,the liquid metal eight-element Fabry-Perot antenna linear array is designed and fabricated to demonstrate the wide beam scanning performance and low sidelobe level.