Microwave Absorber Based On Flexible Magnetic Material And LC Resonator And The Software-Driven Automatic Design Method

Microwave absorber is a material which can reduce incident electromagnetic wave interference by sharply absorbing or reducing electromagnetic wave energy on the absorber surface.With the development in this field,people have designed many types of absorber,and the two most popular types are metamaterial absorber and magnetic absorbing material.Metamaterial absorber is based on metallic surface resonating structure,which can be considered as a LC resonator,and can absorb the electromagnetic wave by its electric resonance and circuit loss.And magnetic material can realize the absorption of electromagnetic wave by magnetic loss of the material.Based on the above two kinds of absorption mechanism,we design a magnetic metamaterial absorber using magnetic material and LC resonant structure,and this absorber can achieve dual-peak absorption for electromagnetic wave.By adjusting the resonant frequency,the absorber can achieve a broadband absorption for electromagnetic wave.We firstly realize the dual-peak absorption of magnetic metamaterial absorber with the help of simulation software.Then we propose a software-driven automatic design method based on genetic algorithm to optimize the structure of our absorber.The method unites the simulation software of CST Studio and MATLAB.By changing the structure parameters ceaselessly to adjust the resonance frequency of LC resonator,the genetic algorithm will accurately and conveniently achieve the optimization of absorber design with maximum absorption bandwidth,which gives the best result of our design.Based on above theory and method,we use a magnetic rubber plate(MRP)as the substrate,and design two different absorbers with a disc-ring structure and a # shape structure,respectively.Take the absorber with ‘#' shape surface structure as an example,the optimized results show that the absorber with the total thicknesses of 1.8mm,2.0mm,2.2mm,2.4mm can achieve the-10 dB wave absorption bandwidth from 5-11 GHz,4.5-10 GHz,4-9.5GHz,and 3.5-9GHz,respectively,which are all much wider than the single MRP absorber with the same thicknesses.Finally,by analyzing the equivalent circuit and origin of dual-peak absorbing of our absorber,we verify the design principle of this absorber,and thus lay the foundation for the deep research of magnetic metamaterial absorber in the future.