Research On High-gain,Wideband Microstrip Antenna Loaded With Metasurface

Microstrip patch antenna is widely used in recent years because of its low profile,light weight and easy processing,but this kind of antenna has the disadvantage of narrow band.The methods commonly are used to improve the bandwidth of microstrip antenna either make the antenna large in size,or increase the complexity of design and the difficulty from analysis to manufacture.Through the research of domestic and abroad scholars,it is found that electromagnetic wave can be well controled the metasurface structure.While it is applied to the microstrip antenna,the advantages of low profile of the antenna can be maintained and the disadvantages of the antenna can be improved.This dissertation mainly focuses on the microstrip antenna loaded with metasurface,so that the microstrip antenna can obtain better performance.The specific work is as follows:(1)Two kinds of high gain microstrip antennas are designed by loading metasurface.By replacing the traditional rectangular radiation patch with the metasurface structure,the gain of the single frequency point microstrip antenna is improved,and the final designed microstrip antenna gain reaches 9.06dBi.The size parameters of the rectangular patch microstrip antenna are analyzed by frequency sweeping.The feeding circuit on the bottom of the dielectric plate is loaded with double coupling aperture to make the microstrip antenna work at 7.95GHz and 10.2GHz,and the two working frequency bands of the antenna have high gain through parameter optimization.Finally,the gain of the dual band high gain antenna is 10dBi and 8.9dBi at two working frequencies,which provides the antenna design idea for multi band directional communication system.(2)A broadband microstrip antenna loaded with a single-layer metasurface is designed.The antenna is fed by a stepped aperture of coplanar waveguide.The metasurface is printed on the top of the dielectric plate,and the coplanar waveguide feed circuit is on the bottom.The relative impedance bandwidth of the antenna is about 58.6%(7.2-12.5 GHz),covering the whole X-band,with peak gain and average radiation efficiency of 92.1%.(3)Based on the single-layer metasurface microstrip antenna,a broadband microstrip antenna loaded with dual-layer metasurface is designed.One layer of metasurface is printed on the top of dielectric plate with stepped aperture at the bottom.Another layer of metasurface is printed directly on the dielectric plate and placed above the antenna.In order to increase the coupling between the metasurface and the stepped aperture of the bottom of the dielectric plate,a non-uniform dual-layer metasurface structure is designed.The size of the rectangular patch element of the upper layer is slightly larger than that of the lower layer.The results show that the antenna has a wide impedance bandwidth of 95.6%(4.8-13.6 GHz)and a peak gain of 9.1dBi due to the combined action of non-uniform dual-layer metasurface and stepped coupling aperture.The simulation results are in good agreement with the test results.In this dissertation,the characteristics of the microstrip antenna are studied and designed by loading the metasurface,which provides a certain reference value for the investigation and detection in the military field and ultra wideband short-range indoor positioning.