Research On X-band Frequency Selective Surface Radomes

Radome is an important part to protect the antenna from the external environment.Ordinary dielectric radome does not have the function of frequency selective,while the radome using frequency selective surface technology has a strong suppression effect on the electromagnetic wave of the frequency outside the passband,which can achieve the purpose of antenna stealth.This thesis focuses on the frequency selective surface radome,combined with the research project.The content of this thesis can be summarized as follows:Firstly,this thesis briefly introduces the related concepts of the research content,explains the research status and existing problems at home and abroad,expounds the research background and significance,and discusses the relevant theoretical basis of the research content.Secondly,high performance X-band frequency selective surface,high performance X-band frequency selective surface radome and frequency reconfigurable frequency selective surface are studied.The specific research content includes three parts:1.High performance X-band bandpass frequency selective surface design A new type of frequency selective surface is formed by cascading two ring-shaped frequency selective surfaces.The frequency selective surface has the advantages of low loss in passband,steep drop in both sides,high out of band suppression and wide stop band.The simulation results show that the loss of the FSS is less than 0.2d B in the 8.5GHz ～ 9.5GHz passband frequency range;the stopband frequency ranges of the left and right passband are4.3 GHz ～ 7.0 GHz and 11.3 GHz ～ 17.4 GHz,respectively;the transition bandwidth of the left and right passband transmission coefficients down to-20 d B is 1.5GHz and 1.8GHz,respectively.2.Research on high performance X-band bandpass frequency selective surface radome According to the characteristics of engineering application,the finite large frequency selective surface radome and X-band horn antenna are simulated and analyzed.The prototype radome is manufactured on the basis of simulation.The test results show that the VSWR increases by 0.2,the maximum radiation direction gain decreases by less than 1.5d Bi,and the maximum radiation direction changes within ± 2 ° when the horn antenna is equipped with frequency selective surface radome,The half power beam width changes within ± 3 °and within the allowable range of engineering application.The results verify the feasibility of high performance X-band frequency selective surface radome.3.Frequency reconfigurable frequency selective surface designBy loading varactor diodes on the traditional frequency selective surface,the filtering characteristics of the frequency selective surface can be changed to achieve the purpose of frequency reconfiguration.The simulation results show that when the capacitance of the varactor changes from 0.1p F to 0.4p F,the center frequency of the passband of the frequency selective surface changes from 12 GHz to 6.4 GHz,the adjustable range reaches 60.9%,the relative bandwidth of the passband remains unchanged at 5%,and the maximum loss in the passband is 1.1d B.Finally,the research contents are summarized and the problems that need further research are discussed.