Research On Beam Reconfigurable Fabry-Perot Antenna Based On Gradient Metasurface

The Fabry-Perot(F-P)resonator antenna,consisting of feed,partially reflected surface(PRS),and metal floor,is a new high-gain antenna that has gained increasing attention from researchers due to its advantages of low profile,low cost,space feeding,and potential application value in various fields such as cellular base stations,satellite communication,radar systems,remote sensing,and cognitive radio.As modern communication technology rapidly develops,research on the F-P resonator antenna has shifted towards multifunctionality,multi-beam,reconfigurable,and intelligent direction.Phase gradient metasurface(PGM),a special metasurface designed by Nanfang Yu et al.to prove the generalized Snell law,is widely used in antenna beam control because it can use a predetermined plane wave vector to control the transmitted/reflected wave direction.This paper focuses on the beam reconfigurable performance of the F-P resonant antenna based on PGM.The paper’s main contributions are summarized as follows:(1)Design of a mechanically adjustable Fabry-Perot resonator antenna: A PGM based on hexagonal complementary unit cell structure is designed,and the metasurface is used as a resonator antenna PRS to obtain a large beam tilt angle.The F-P resonator antenna beam can be mechanically adjusted by changing the phase distribution on the aperture surface through the mechanical rotation of the PGM.Measured results indicate that the antenna achieves approximately θ =50° of elevation angle at eight azimuth angles(ψ = 0°,45°,90°,135°,180°,225°,270°,315°).Furthermore,the overlapping-10 d B impedance bandwidth was found to be 5.7%(5.50-5.82 GHz),with a peak gain of 14 d Bi across all states.(2)Design of an electronically adjustable Fabry-Perot resonator antenna: A singlelayer PRS loaded with a PIN diode is designed to divide the PRS into two regions.The beam is adjusted by controlling the ON/OFF state of the PIN diode in two regions to change the phase distribution of the aperture surface.Results show that the F-P resonator antenna can be switched in +10°,0°,-10° three beam states,and realize a gain of 14.5 d Bi.The above PRS is extended into a double-layer,each layer is still divided into two areas.The F-P resonator antenna will have 7 beam directions if the three reflection phase states of the double-layer PRS unit cells are combined in pairs in these two regions.Results show that the double-layer PRS resonator antenna beam in 0°,± 2°,± 54°,± 52° for the free switch,further broadens the range of the adjustable beam.