Design And Electromagnetic Performance Of Dielectric Metamaterials Based Absorbing Concrete

Electromagnetic waves provide people with convenience,but also negatively affect people’s health,electronic equipment,information safety "invisible" military bunkers and other defense facilities also poses a serious threat.In order to prevent electromagnetic interference,it can be started from the building itself,as most commonly used the building materials.Concrete has been extensively studied to improve its wave absorption performance.In this thesis,the dielectric metamaterial absorbers are combined with concrete in buildings to explore the wave absorption performance.The CST microwave studio is used to optimize the design and calculation of dielectric particles and steel structure in the frequency band of 8 ～ 12 GHz to explore the dielectric metamaterial absorbing concrete,and the resonance mechanism and absorption peak modulation are investigated.(1)A single-frequency dielectric metamaterial absorbing concrete with 98 %absorption at 9.82 GHz is designed and prepared,and the absorption is caused by the electromagnetic resonance of the dielectric particles.The absorption is insensitive to polarization angle and incidence angle,and has a good absorption effect with wide incidence angle.The absorption frequency red shifted with the increasing of sizes of dielectric particles or the permittivity of dielectric particles.The experimental results and simulation results match well.(2)Dual-frequency dielectric metamaterial absorbing concrete based on different edge lengths,different dielectric constants and dual-level Mie resonance of high dielectric particles are designed.The structures based on dielectric particles with different edge lengths have 95.5 % absorption at 10.59 GHz and 95.7 % absorption at11.60 GHz;the structures based on dielectric particles with different dielectric constants have 98.8 % absorption at 10.56 GHz and 96.3 % absorption at 11.12 GHz;the structures based on high dielectric particles with dual-stage Mie resonance,the absorption at 9.24 GHz is 99.4 % and 95.0 % at 10.50 GHz.All three structures achieve high absorption and are insensitive to resonance and incidence angles.The absorption is caused by the electromagnetic resonance of the dielectric particles.The absorption peaks can be tuned individually or simultaneously by changing the dielectric particle size edge length or dielectric constant.(3)Broadband absorbing concrete was designed with dielectric metamaterial with different edge lengths,different dielectric constants,both of which can broaden the absorption peak with the increase of dielectric particles.However,as the number of dielectric particles increases,the position relationship between the particles,the difference in edge-length dimensions between the particles and the difference in the dielectric constants of the particles must be adjusted.The frequency range of absorption above 70 % is 1.159 GHz when 16 dielectric particles with different sizes were used.And the frequency range of absorption above 70 % is 1.331 GHz when 16 dielectric particles with different permittivity were used.