Research On Broadband And High-gain Metalens Antenna Technology At E-band

Metalens antennas have attracted growing attention due to their high gain and low-profile.However,the metalens antenna has shortcomings,such as narrow bandwidth and complex design,which limit the application of the metalens antenna.This thesis studies the design method of broadband and high-gain metalens antennas.The main research contents of this thesis are as follows:A broadband high-gain metal metalens antenna is designed and studied.According to the performance requirements of the lens antenna,the phase compensation characteristics are obtained.And the metalens is designed as a 3bit phase distribution,so as to obtain the ideal phase curve of each element of the metalens.To achieve the phase characteristics of different elements,a variety of different metal patch structures are used.And genetic algorithms are used to optimize the element structures that conform to the ideal phase curve as much as possible,thereby achieving a broadband.At the same time,there is no air gap between the layers,which has good mechanical stability and can achieve a wide phase coverage with the low profile.A slot antenna designed using substrate integrated waveguide(SIW)technology is used as the feed antenna.Compared with the horn feed,the SIW slot antenna can further reduce the overall profile of the metalens antenna.Based on the above element and feed antenna,a metalens antenna is designed which has a gain of23.28 d Bi at 74.23 GHz.And its 3-d B gain bandwidth is 71.78-80 GHz(10.83%).Compared with the feed antenna,the main beam width of the metalens antenna becomes narrower and the gain is greatly improved.According to the phase requirements of different elements,a dielectric column element is designed,which is composed of a square dielectric column and a square hole.To achieve different element structures that meet the requirements,we study the influence of the height of the dielectric column and the depth of the square hole on the phase of the element.Then,the above-mentioned dielectric element is used to form an all-dielectric metalens lens,and the horn antenna is used as the feed source.Finally,the antenna was processed using 3D printing technology,and the antenna was measured in a microwave darkroom.The lens antenna works at 60-90 GHz,and the test results show that the 1-d B gain bandwidth of the antenna is 73.1-90 GHz,and the highest gain in the entire frequency band reaches 29.7 d B at 80 GHz,which is an increasing of 12.9 d B compared with the feed antenna.In the entire frequency band,the gain is higher than 23 d B.The aperture efficiency is greater than 20% in the working frequency band,and the simulated aperture efficiency reaches the maximum of 52.55% at80 GHz.On the basis of the above research,in order to further improve the gain bandwidth performance of the metalens antenna,the design principle of the broadband metalens antenna is studied.According to the design principle,the ideal phase distribution of the metalens and the ideal phase curve of the element are obtained.The genetic algorithm is used to optimize the all-dielectric element to obtain the element structure that conforms to the ideal phase curve as much as possible.Using this unit to design a metalens antenna,the antenna gain can reach 29.7 d Bi,and the 1-d B gain bandwidth can reach 72.1 – 114 GHz.Compared with the original metalens antenna,the gain bandwidth is greatly improved.