Research On Ultra-Wideband,Angle And Polarization Stalble Microwave Absorber

With the rapid development of informatization and digitalization,electronic equipment has been widely popularized and applied.Meanwhile,it has also brought unprecedented challenges such as electromagnetic interference,electromagnetic radiation and information security.Under this background,the structure of the absorber emerges at the right moment and continues to develop up to now,more attention is paid to its design indicators,such as ultra-broadband,wide oblique incident Angle,polarization stability and low thickness.Therefore,this paper will focus on the discussion of ultra-broadband,oblique incidence and polarization stability,miniaturization method and tradeoff strategies among them.(1)In order to realize ultra-broadband absorbing covering L?Ku band,a 1-18GHz 3D metamaterial absorber structure was designed.Under vertical incidence,the absorptivity of both TE and TM polarized waves is more than 90%in the 1-18 GHz frequency band.under oblique incidence,the maximum oblique incidence angle of TE polarizable wave can reach 60~o,while in TM it is only 20~o,At this time,the corresponding unit period is17?17?33 mm~3;(2)In order to improve the oblique incident absorption characteristics of TE and TM waves,an absorbing structure based on the combination of 2D and 3D was designed.The realization of two-dimensional absorbing structure adopts the design method of circuit analog absorber(CAA),and combined with genetic algorithm to avoid blind sweep optimization in design work,improve design efficiency and analyze the mechanism of 2D and 3D composite structure to realize broadband absorption.Under vertical incidence,the absorptivity of both TE and TM polarized waves is more than 90%in 1-18GHz frequency band.Under oblique incidence,the maximum oblique incidence Angle of TM and TE polarized waves is 60~oand 30~o,respectively,corresponding the unit period is16?16?34 mm~3;(3)In order to improve the output quality of genetic algorithm and reduce the complexity of the structure,the algorithm was improved and two two-dimensional circuit analog absorber were designed.Structure 1:Under vertical incidence,the absorptivity of TE and TM polarized waves can be more than 90%in the frequency band range of 1-18 GHz.Structure 2:Under vertical incidence,the absorptivity of TE and TM polarized waves can be more than 90%in the frequency band range of1-18GHz.The maximum oblique incidence Angle of TE and TM polarized waves can both reach 30o,The period size of the first unit is59.71?59.71?38.3 mm~3,and the period size of the second unit is56.76?56.76?27.36 mm~3;(4)In order to further increase the oblique incidence Angle and improve the polarization stability in L band,absorber based on perfect matching layer(PML)was designed,and the dispersion regulation method based on the Krammers-Kroning relationship was adopted.the absorptivity of TE and TM polarized wave can reach 90%in the frequency band of 0.87?2.5 GHz.Under oblique incidence,the maximum oblique incidence Angle of TE and TM polarized wave is:40oand 50o,corresponding the unit period is34?34?34 mm~3.