Design Of High Performance Wide-Band Circuit Analog Wave Absorbing Structure

Wave absorbing material refers to the effective absorption incident electromagnetic waves so that the energy of reflected and transmitted waves is small.Absorbing materials are mainly used in military stealth,radar RCS reduction,microwave darkroom,electromagnetic compatibility and other fields.In recent years,with the increasing demand for wave absorption performance,circuit simulation of wave absorption has become a research hotspot.Many ultra-wideband and low-profile wave absorption structures have been produced,but at the same time,high performance and large Angle wave absorption are also difficulties.In this paper,the theoretical basis of the equivalent circuit and the differential evolution algorithm were used to optimize the design of a highperformance absorbing structure,so that the Angle absorbing was significantly improved.The main research contents are as follows:1.Firstly,starting from impedance matching,the range of real part and imaginary part of input impedance required to satisfy S11 of-40 dB is calculated.Then starting from the equivalent circuit,the analytical formula of the existing frequency selection surface is analyzed and calculated.Taking-40 dB as the high performance index,the optimal band,single ring and double ring-40 dB bandwidth is optimized by theory and simulation respectively.The results show that the theoretical calculation results and simulation results are basically consistent.Then the causes of each resonance point in the band,single ring and double ring bandwidth are discussed qualitatively.All the above structures are single-layer designs.In order to achieve high performance wave absorption with larger bandwidth,multi-layer designs are carried out later,and the results show that the wave absorption bandwidth can be greatly expanded.2.For the analytic optimization design of multi-layer structure,there are usually many parameters and it is impossible to find the optimal solution.Differential evolution algorithm has the characteristics of strong global search ability,but weak local search ability,so that it is easy to roam in the later period,and the combination of differential evolution algorithm and particle swarm optimization algorithm can perfectly solve this problem.In this paper,the combination of these two algorithms,through MATLAB and CST interactive simulation optimization,first designed a double-layer double-ring structure,-10 db percentage bandwidth reached 161.23%,proved the feasibility of the algorithm.After that,a number of double-layer absorbing structures were designed.Through comparison,it was found that the double-layer cross structure had 62.46%-40 db absorbing bandwidth.The machining test shows that the structure has high performance in 6~12GHz absorbing point.Finally,the upper end of the structure is loaded with a wide Angle matching layer to improve the incident Angle absorbing.3.At the end of the paper,the author firstly verified the scheme to improve the performance of the original structure by using new technologies such as tunable and water medium.Firstly,the tunable structure of graphene was designed,and a preliminary understanding of the tunable technology was gained.Then,the above structure was applied to make the graphene Angle tunable to improve its angular wave absorption performance.The characteristics of dispersion of water medium and high imaginary part of dielectric constant are used to improve the performance of absorbing structure.Finally,the three-layer structure was designed for verification,and the bandwidth was calculated.It was found that the S11 bandwidth of-40 db reached 80%.