Research On Equivalent Electromagnetic Parameters Theory And Application Of Structural Composites

Structural radar absorption material possesses both wave absorption and load bearing functions,which is an important development direction in the field of stealth materials.The electromagnetic properties of structural materials are studied mainly from the complex electromagnetic parameters to calculate their equivalent electromagnetic parameters.The calculation of equivalent electromagnetic parameters is an important but difficult problem in the fields of electricity,light and magnetism.This paper focuses on the equivalent electromagnetic parameter theory and application of structural composites.The analysis method of the electromagnetic characteristics of honeycomb structured materials,the method of equivalent parameters based on the strong disturbance theory,the application of typical honeycomb materials and the equivalent parameter model of metamaterials are studied.Firstly,the geometric structure and impedance matching of honeycomb materials are introduced.Then the moment method based on the surface integral equation is used to analyze the electromagnetic scattering characteristics of honeycomb materials.Finally,the free space method,which is widely used in material parameter testing,is discussed,and the honeycomb model is simulated to verify the feasibility of the method.Based on the homogenization and strong disturbance theory,the equivalent electromagnetic parameters and reflection coefficient of honeycomb structure are derived,and the formula of equivalent dielectric constant with dispersion characteristics is modified.The reflection coefficient of honeycomb material was obtained by simulation,and the absorbing property of honeycomb was analyzed.The changes of the equivalent electromagnetic parameters and the reflection coefficient of the honeycomb structure with the geometric characteristics are studied,including the thickness of the honeycomb and the frequency of the incident wave.Then,the electromagnetic parameters of the material are deduced when the electromagnetic wave is incident obliquely.It is found that the electromagnetic parameters are affected by the incident angle.Therefore,it is necessary to equivalent the anisotropic composite material.At this time,the electromagnetic parameters are all in the same direction and easy to calculate.Then,the electromagnetic scattering characteristics of finite size honeycomb structure are investigated,and the RCS is compared with the equivalent finite large uniform structure model,and the correctness of the method is verified.Finally,the honeycomb material is applied to the material filling of airplane wing.Finally,the honeycomb material was applied to the filling of the aircraft wing,and the scattering characteristics of the all-metal wing and the wing with absorbing structure were compared and analyzed.For metamaterials,the S parameter inversion method and the improved Kramers-Kronig method are used to solve the equivalent electromagnetic parameters.Using these two methods to compare and analyze the electromagnetic parameters and refractive index of the split resonant ring and the multi-layer weakly coupled fishing net structure verifies the correctness of the method,and also verifies the negative refraction characteristics of the two types of structures.