Research On New Technologies Of Electrically Controlled Beam Reconfigurable Array Antennas And Metasurface Antennas

Metamaterials are composed of periodic or non-periodic subwavelength units.These artificial structures have extraordinary physical and electromagnetic characteristics.The discovery of metamaterials has made scholars make a historic breakthrough in the regulation of electromagnetic waves.Metasurfaces are two-dimensional metamaterials,which can effectively regulate the polarization mode and wavefront phase of electromagnetic waves.Compared with metamaterials,metasurfaces have the advantages of low profile,low loss,low cost,and easy processing.The superiorities of metasurfaces have made it widely used in antenna applications by scholars.In this paper,electronically controllable beam reconfigurable array antennas and new technologies of metasurface antennas are the main research contents.Firstly,a high-gain dual circularly-polarized(CP)Fabry_Perot resonant antenna is designed by using the metasurfaces to control the electromagnetic wave polarization mode.The dual-linear-polarized H-slot microstrip antenna is designed to realize dual-port feeding and increase the communication capacity.The microstrip patch antenna is placed in the Fabry-Perot cavity to overcome its shortcoming of low gain.The gain is increased by 7.15 d Bi at 12.5 GHz.A linear-to-circular transmission metasurface is mounted on the top of Fabry-Perot resonant antenna to achieve dual-circular polarizations.Simulation and experimental results show that the peak gains of the antenna in LHCP and RHCP are 12.78 d Bi and 12.89 d Bi,respectively.And the corresponding 3-d B bandwidth is 12.07-13.68 GHz and 12.16-13.74 GHz.The relative bandwidths are 12.5% and 12.2%,respectively.Then by using metasurfaces to control the wavefront phase,a high gain multibeam folded transmitarray antenna(FTA)is designed.The antenna consists of a main reflector,a sub-transmitarray(transmissive metasurfaces unit)and 5 feeding antennas(2×2 microstrip patch array).The 90° polarization conversion reflective metasurface units construct the main reflector,and five 2×2 microstrip patch arrays are embedded in the center of the main reflector.The transmissive metasurface unit cells which can realize 90° polarization conversion and phase compensation construct the sub-transmitarray.The simulation results demonstrate that the multibeam FTA can achieve a scanning range from-10° to 10°.When the center feed is fed,the side-lobe levels in the E and H planes are lower than-20 d B and-15 d B respectively at 30 GHz.The maximum gain is 28.9 d Bi,and the aperture efficiency is 24.6%.Finally,the PIN diode and the metasurface are integrated to realize the dynamic control of electromagnetic(EM)waves.An electrically controlled beam reconfigurable folded reflectarray antenna is designed.The active metasurface units which can realize 90° polarization conversion and phase compensation at the same time constitute the main reflector.The 180° reflection phase difference is realized in real time between the “on” and “off” states of the PIN diode.The sub-reflector consists of a polarized grid.A 2×2 microstrip patch array is embedded in the main reflector as a planar feed to achieve the integration.Simulation and experimental results show that the antenna achieves two-dimensional scanning range of ±60° at 12.5GHz,a peak gain of 17.07 d Bi,and an aperture efficiency of 13.02%.