Research On Electromagnetic Properties Of Microwave Absorbing Matamaterials Based On M-type Barrium Ferrite

The rapid development of electronic information technology and the popularization of large-scale electronic and electrical equipment in national defense and civil fields ensure the convenience of citizens and providing life convenience,but at the same time it's inevitabe to give rise to many practical problems,such as electronic countermeasures,harmful electromagnetic wave protection and so on.Therefore,the research on demand-oriented microwave absorbing materials has to be carried out.In terms of the types and forms,it can be divided into two fields: dielectric absorbing materials and absorbing metamaterials.M-type barium ferrite,Ba Fe₁₂O₁₉,is a typical double-complex dielectric magnetic material,which is an excellent candidate for microwave absorbing materials because of its good electromagnetic properties and resonance.Its microwave absorbing performance can be modified by doping and ion substitution.In this paper,Co²⁺ and Ti⁴⁺ ions were used to replace Fe³⁺ in Ba Fe₁₂O₁₉.The samples exhibit good electromagnetic wave loss characteristics,in which the microwave absorbing performance is mainly concentrated in the lower frequency range of 2-10 GHz,and it has excellent characteristics in terms of maximum reflection loss characteristics and broadband absorption characteristics.In the designment and optimization of the absorbing metamaterials,this paper expand the single-frequency wave-absorbing metamaterial to multi-frequency response using the arrangement and combination of structural units and design a wide-band absorbing metamaterilal by loading lumped resistors in conventional microwave absorbing metamaterial.During the simulation by CST Microwave Studio,it was found that the coupling between the structures in vertical arrangement is obvious,resulting in a large difference in the intensity of each absorption peak,while in planar arrangement the absorbing intensity decreases due to the periodic change of the structure.In the rhombus ring absorbing metamaterial loaded with lumped resistance,the surface current excited by the incident electromagnetic wave is converted into heat dissipation by the lumped resistance,which increases the resistance loss mechanism for the overall structure,realizing the wide-band incident wave absorption.The microwave absorbing rate can reach 90% in the range of 9.0 – 15.6 GHz and 99% in the range of 12.5 – 14.6 GHz.Finally,attempt to combine the high dielectric loss material doped M-type barium ferrite material with the microwave absorbing metamaterial.The M-type barium ferrite is used as the dielectric material in the metamaterials,to combine the advantages of structural design and optimization of metamaterials to achieve a better performance.The simulation results show that due to the addition of the metal resonance layer,the loss characteristics of the M-type barium ferrite have changed.At the equal thickness,the microwave absorbing peak moves towards lower frequency,but the absorbing peaks caused by metamaterials are retained.The numbers of frequency points for microwave absorbing and abbsorbing bandwidth have been increased.