Research On Reflectarray Antenna Based On High-Power And Broadband Characteristic

The reflectarray antenna,as a new type of antenna that combines the advantages of parabolic and phased array antennas,overcomes the problems of traditional parabolic antennas such as large volume,high profile,and processing difficulties.Moreover,the element structure is independent and controllable,and can achieve various functions such as polarization regulation,beam scanning,and beam shaping.The reflectarray antenna adopts a space feed method,it could avoid the complex feeding network in phased array antennas,reduce feeding losses,and improve the radiation efficiency of the antenna,which has a very broad application prospect.However,most of the reflectarray antenna have problems such as limited power capacity and narrow bandwidth performance.Based on the above background,this paper studies the problem of the power capacity and bandwidth of the reflectarray antenna.The main content includes the following two aspects:1.For the problem of insufficient power capacity of the traditional reflectarray antenna,this paper proposes a revised type of high-power reflectarray antenna.The revised element adopts the double square rings patch structure,which homogenizes the surface electric field of the element by adding several layers of dielectrics on the surface.The revised element reduces its maximum field strength,and thereby improves the power capacity of the reflectarray antenna element.Under infinite periodic conditions,the maximum surface field strength of the revised element is 0.1565×10~4V/m,which reduces the maximum field strength by 18times compared to traditional element,and theoretically increases the power capacity by about320 times.Under finite periodic condition,the maximum field strength of traditional reflectarray antenna array is 6.84×10~4V/m,the maximum power capacity is about 1.924 KW,while the maximum field strength of the revised reflectarray antenna array is 96.29 V/M,and the maximum power capacity can reach 970.69 MW.The above results show that the power capacity of the revised reflectarray antenna has been significantly improved in theory.In order to further verify,this paper conducted physical processing on two different types of reflectarray antennas.Through detailed experimental testing,it was found that the revised reflectarray antenna did not observe surface flashover phenomenon at 1 GW power,and still maintained the preset radiation beam in the normal direction of the array under this power.2.For the problem of wideband of the reflectarray antenna,this paper designs a shared aperture dual-band antenna based on the structure of reflectarray antenna,which realizes dual-band function by using the dual focus and polarization isolation characteristics of Cassegrain antenna.The antenna is composed of a main reflector,a sub-reflector and two feeds in different frequency bands.The designed antenna can simultaneously operate in two frequency bands(W-and Ka-bands).The diameter of the main-reflector is 130 mm,and that of the sub-reflector is 40 mm.The simulation results show that the peak gain of the antenna is38.8 d Bi with the aperture efficiency of 46.7%,and its sidelobe level is lower than-15.2 d B at94 GHz.The peak gain of the antenna is 30.9 d Bi at 35 GHz and the aperture efficiency is54.8%.Moreover,the sidelobe level is lower than-16.3 d B at 35 GHz.The above results show that the designed antenna has good radiation characteristics in both frequency bands,and the aperture efficiency of the dual-band antenna is around 50%.This provides a promising solution for improving the aperture efficiency of the dual-band Cassegrain antenna,reducing costs and complexity.