Research Of Miniaturized Multi-band Frequency Selective Surface

Frequency Selective Surfaces(FSSs)are infinite periodic structures consisting of metal patches or slot elements,which can be used as radome,antenna subreflector.As a spatial filter,its frequency response is related to the frequency,polarization direction and angle of the incident wave.Due to the complex electromagnetic environment and the limitation of practical application space,the research of miniaturized multi-band frequency selective surface has practical significance.The main work and innovation of this paper are as follows:1.The application of bending technique in the design of miniaturized multi-band FSS is studied.Firstly,based on the complementary structure of the bent grid,a dual-band frequency selective surface with cell size of 0.03? ×0.03? is realized,which has high angle stability because of the miniaturization of cell size.Secondly,the bent dipole element is obtained based on the bent grid,and the bending order of the bent dipole is increased.Finally,the four stopband and four passband filter responses of the bending dipole and its corresponding slot element are realized.2.A single-layer frequency selective surface(FSS)is designed by using a metal grid and a bent square ring structure.Then,by using cascaded technique,the structure is cascaded with the loaded strip square ring to achieve four pass band filter response with angle stable.3.The 3D folded ring structure is obtained based on the metallized through hole,and the filter response of the structure is different under different polarizations.According to the electric field current distributions of each resonant point,the corresponding equivalent circuit is obtained.4.Based on the characteristic that the first resonant point is a transmission zero,a grid array is added in the middle layer of the composite element to realize the miniaturized dual-band filter response with wide upper stopband.The cell size is only 0.066? ×0.066?,the upper stopband corresponding to-10 d B bandwidth is 9 GHz.The sample is made and tested,and the test result proves the correctness of the design.