A Metasurface-Based Broadband And High Gain Antenna Design

With the upgrading and continuous evolution of wireless equipment,our life and defense technology are more and more modern,and the application of wireless equipment is more and more extensive.People put forward more and more pressing needs on the information capacity?transmission quality and service diversity of wireless communication technology,and it is very important that people put forward higher requirements on antenna performance.Previously,many people have done a lot of research on the antenna pattern reconstruction?polarization methods and so on,and also achieved a lot of results.Nowadays,broadband and high gain antennas and arrays have becoming one of the important topics in antenna research domestic and overseas.Fabry-Pérot?F-P?resonator antenna can improve the gain very well,and has simple structure and good directivity.However,narrow bandwidth is its obvious disadvantage.How to improve the bandwidth and ensure high gain is a subject worthy of study.Metamaterial is a kind of artificial electromagnetic period structure,whose period is much shorter than wavelength.It has many extraordinary physical characteristics,such as negative refractive index?inverse Doppler effect?inverse Snell refractive effect,ect.It has been applied in new stealth?smart skin?radar absorption?antenna and other fields.Traditional array antenna has comparable period and wavelength,while metasurface antenna has the advantages of sub-wavelength unit size,period is much smaller than wavelength,and it is easier to achieve miniaturization.The main contents of this paper are as follows:1.To improve the bandwidth?gain bandwidth and impedance bandwidth?and the high gain,metasurface is used to design the F-P resonatoe antenna.The overall size of the proposed antenna is only 0.09 times the wavelength corresponding to the central frequency of 5 GHz.The overall performance of the antenna is optimized by genetic algorithm?GA??mainly considering gain bandwidth and impedance bandwidth?.For the broaddest bandwidthrequirement,the optimized impedance bandwidth(S₁₁?27?-10dB)reaches 44%,the 3dB gain bandwidth exceeds 46%,and the maximum gain is 11.8dBi.Finally,in order to verify the design idea of the first antenna,the physical model of the antenna is fabricated and tested by Aglient E8361A vector network analyzer.Its S parameters,gain and pattern are in good agreement with the simulation results.2.Circular polarized antennas have been widely used in practical life.The axial ratio bandwidth of circular polarized antenna is broadened by using metasurface,and the impedance bandwidth and gain performance are not affected.The microstrip patch antenna is used as the feed to realize the conversion from linear polarization to circular polarization by changing the shape of the patch,and the ultra-surface wide axis ratio bandwith and impedance bandwidth are adopted.Finally,the proposed antenna profile has only 0.06 times the wavelength corresponding to the central frequency,the impedance bandwidth(S₁₁?27?-10dB)reaches 49.18%,and the specific bandwidth of the3dB axis exceeds 22%.