Experimental And Simulation Research On Lightning Characteristics Of Typical Structure Electromagnetic Metamaterial

Because of its special excellent electromagnetic properties,electromagnetic metamaterial has great potential and development space in the field of radar antenna,stealth,electronic countermeasures and many other equipment technology fields.The radome of metarmaterial radar is usually made up of an artificial structure unit with periodic arrangement.It is different from the traditional non conductive composite material.The particularity of a large number of metal elements in the internal structure makes the response of the metamaterial radar cover change in the lightning environment,and the lightning protection problem is more prominent.Lightning protection for aircraft radome is an important component of aircraft lightning protection.The lightning protection of metamaterials is also a key step to be solved.In this paper,the finite element software COMSOL is used to simulate and analyze the electric field distribution of three typical structure metamaterials,and the influence of the structure type and the structure parameters on the electric field distribution is obtained.Based on the particularity of the electric field distribution in the metamaterial lightning environment,the study on the lightning attachment and protection characteristics of metamaterial is carried out from the two aspects of experiment and simulation.The results of the research can provide theoretical basis and reference for the lightning protection of metamaterial,and have certain guiding significance for the optimization of the lightning protection structure of the radome.The main conclusions of this paper are as follows:(1)The shape of metal element has little influence on the electric field distribution of metamaterial structure.The topology of metamaterial unit has a certain influence on the distribution of electric field.The electric field intensity of the metamaterial surface with electrical connection is high,and it is easy to produce the upstream pilot,and the field strength of the adjacent independent metal single element in the inner part of the non connected structure metamaterial is high.It is easy to break down the small gap and discharge along the surface.(2)The increase of dielectric constant of the metamaterial and the increase of thickness can weaken the induction electric field around the inner metal element;the accumulation of surface charge leads to a significant increase in the intensity of the electric field in the skin,and increases the danger of the skin breakdown.(3)Under lightning environment,the probability of lightning attachment to metamaterials is higher than that of traditional cozmposite materials.The structure of the metamaterial will play an important role in shielding the electric field of the internal antenna.The lightning protection of metamaterials should be concerned about its own structure.(4)The protection effect of the lightning diverter strip on the traditional composite material is remarkable,but the protection range of the metamaterial is reduced,the distribution of the diverter strip needs to be tighter,and the optimized design of the lightning protection structure should be considered.The shape of the inner cell has little effect on the protection effect of the lightning diffuser,but the topological form of the unit has a certain effect on the protection effect.The protective effect of the lightning diverter strip is less than that of the non electrically connected structure.The lightning protection needs to shield the ground position of the metamaterial of the non electrically connected structure and shield the metamaterial with the electrical connection structure as a whole.