Research On Preparation And Performance Of Broadband Resistive FSS Radar Wave Absorbing Structure

Absorbing materials and their structures have important application value in national defense and civil fields such as radar stealth,electromagnetic shielding,communication systems,and human protection.An excellent absorbing structure not only needs to meet the performance requirements of broadband absorbing and low reflectivity,but also needs to meet the application requirements of light weight,thin thickness,high strength,and corrosion resistance.In this thesis,for the design and preparation of broadband frequency selective surface(FSS)absorbing structure,the absorbing mechanism,preparation process and characterization method of broadband absorbing structure are studied,and the frequency bands in the C,X,and Ku bands are prepared through optimized design.The high-absorption flat sample.The main research contents of this thesis include:First,the basic electromagnetic theory is introduced,and the reflection law at the plane boundary of the propagation of electromagnetic waves in the lossy medium layer is studied;some common absorbing structures are listed,and the theories and designs of different absorbing structures are carried out.In-depth exploration;the theory of frequency selective surface is analyzed,and the theoretical basis and equivalent circuit model of FSS absorbing structure design are summarized.Second,use CST simulation software to quickly automate modeling and set boundary conditions,focus on simulating the reflectivity of Jaumann absorbing structure and FSS absorbing structure at different frequencies,using genetic algorithms to control the changes of different parameters,and to perform simulation results Discuss and optimize the optimal scheme of resistance-type broadband FSS absorbing structure.Third,through the classification and comparison of the conductive fillers of the resistance layer of the resistive wave absorbing structure,carbon nanoparticles are selected to prepare the resistance layer,and the preparation process of the screen printing is introduced in detail.The four-probe test method was used to characterize the resistance layer and verify the surface resistance value.The change rule of the surface resistance of the conductive ink under different proportions was studied by the method of controlling variables,and the resistance layer meeting the experimental requirements was prepared.Fourth,the preparation technology of the broadband FSS absorbing structure and the measurement method of reflectivity are studied,and the actual sample is prepared according to the finally optimized absorbing structure with better absorption characteristics,and the reflection coefficient and the focusing horn are adjusted by the arched frame and the focusing horn.The transmission coefficient is tested,and the data is processed to obtain the reflectance and absorption coefficient of the FSS absorbing structure.The test results are in good agreement with the simulation results.