Design Of Reconfigurable Antenna Based On Metasurface

With the rapid development of wireless communication system towards the trend of multifunction,high speed,and large capacity,the wireless communication platform integrates multiple antennas.As the number of antennas increases,the volume of the platform becomes larger,and the electromagnetic compatibility becomes worse.Reconfigurable antennas emerge as the times require.By dynamically adjusting the reconfigurable antenna structure,the antenna can work in different modes to meet the needs of different working environments and applications.As a two-dimensional metamaterial,metasurface can manipulate electromagnetic waves flexibly.When the metasurface is applied to antenna design,it can realize the continuous adjusting of operating frequency,transformation of polarization mode,and switching of different radiation modes.Therefore,the research of the reconfigurable antennas based on metasurface have great academic significance.The main research work of this thesis is as follows:1)A frequency reconfigurable antenna based on isosceles triangular metasurface is proposed.It is composed of an isosceles triangular metasurface with periodic arrangement and a slot antenna.The operating frequency of the antenna can be tuned by rotating the metasurface.The simulated and measured results show that,when the metasurface rotates from 0° to 90°,the operating frequency can be tuned from 2.38 GHz to 3.82 GHz with a wide tuning range of 46.5%.Good radiation pattern is obtained,and the peak gain is 5.62 d Bi.2)A polarization reconfigurable antenna based on eight-shaped metasurface is proposed.It is composed of an eight-shaped metasurface with periodic arrangement and a slot antenna.By rotating metasurface,three states of linear polarization(LP),left-handed circular polarization(LHCP),and right-handed circular polarization(RHCP)can be transformed.The simulated and measured results show that the antenna realizes the change between linear polarization and circular polarization.In the circular polarization state,the-10 d B impedance bandwidth is 35.4%(2.84 GHz-4.06 GHz)and the 3 d B axial ratio bandwidth is 10.2%(3.34 GHz-3.70 GHz).In the linear polarization state,the-10 d B impedance bandwidth is 37.4%(2.74 GHz-4.00 GHz).Good radiation pattern is obtained,and the gain in the operational frequency band is more than 6.0 d Bi.