Design And Research Of Microwave Low-frequency Broadband Absorber Based On Metamaterial

With the rapid development of electronic information technology,both military and civilian fields raise higher requirements for Electromagnetic Compatibility.Metamaterial absorbers use metamaterial design flexibility to effectively regulate the electromagnetic parameters of the absorbers by designing the cell array structure to achieve electromagnetic wave absorption,which is an important research area in the technology of Electromagnetic Compatibility.At present,the study of broadband metamaterial absorbers has become a popular direction in the microwave band,while broadband absorbers often have complex structures,large thicknesses,and poor low-frequency performance.It is a difficult task to achieve broadband absorption at low-frequency with thin thicknesses.To address these problems,this paper focuses on microwave low-frequency broadband metamaterial absorbers and carries out the following work:(1)The influence of the conductivity parameter on the absorption performance and the frequency limitation conditions for adjusting the conductivity parameter are analyzed to show that the reasonable adjustment of the conductivity in the microwave frequency band can increase the loss and thus expand the absorption bandwidth,and the analysis is tested by numerical simulations with the double-ring-type metamaterial absorber as the research object.The results show that there is an optimal value of the conductivity parameter,which can improve the absorption efficiency and expand the absorption bandwidth when matching a certain thickness of the dielectric substrate.(2)An H-type metamaterial absorber compounded by different conductivity is designed,which effectively expands the absorption bandwidth by reasonable regulation of the conductivity and reduces the resonant frequency of the absorber by adjusting the structure width and spacing width.The simulation results show that the metal resonant H-type metamaterial absorber has only 60%absorption at 13.45 GHz,while the H-type metamaterial absorber based on different conductivity composites achieves > 90% absorption in the range of 9.64 GHz ～ 10.8 GHz.(3)A microwave low-frequency broadband absorber based on low conductivity metamaterials is designed.By stacking multilayer low conductivity resonant rings,the properties of the multilayer structure to improve low-frequency performance and the broadband absorption property of low conductivity metamaterials are utilized to achieve microwave low-frequency broadband absorption.The results show that the absorption at 0.89 GHz ～ 17.01 GHz is greater than 90%,and the operating band covers the full L,S,C and X bands and most Ku bands.It also has polarization insensitivity and wide incidence angle,and the thickness is only 3 mm.