Research On Target Simulation And Unidirectional Devices Based On Electromagnetic Metasurface Technology

With the development of metasurface technology,it has greatly expanded the research scope of electromagnetic fields such as antenna performance promotion and stealth protection.The metasurface technology has capabilities of electromagnetic controlled,and the capability of phase controlled is used in beam control,etc.,and adjusting the shape of the scattered wave beam randomly.Therefore,metamaterials have attracted much attention in many fields and are widely applied in the development of various functional devices.Researchers have constructed wave-absorbing arrays using metasurface technology,which can absorb electromagnetic waves in a specific frequency band.The scattering pattern of the 3D real model can be approximated by the metasurface,and the calculation of electromagnetic scattering requires a smaller number of mesh divisions.This feature can be applied to the simulation and the computational electromagnetics acceleration of real targets.The electromagnetic characteristics of the metasurface can change the transmission direction,and then composed a metasurface len.The metasurface can change the direction of wave propagation and absorb waves.Main works of the thesis are presented as follows: 1.The basic concept of the metamaterial and the principle of the metasurface structure are introduced.By designing the resonant unit,magnetic permeability and dielectric constant can be realized in a specific frequency band,thereby achieving control of poynting vector and the electric field polarization.2.The MATLAB has invoked CST by ’com’ interface to build heterogeneous array easily.The metasurface technology is introduced into computational electromagnetics.And coordinate transformation is used to realize that the model with complex surfaces transformed into the model with smooth surfaces.If roughness surfaces instead by smooth surfaces which lead to the numbers of grids reduction to realized computing target RCS quickly.3.The effective dielectric constant and permeability of the square ring structure are extracted by the S parameter inversion theory.And based the Generalized Snell’s Principle,3D structure will be transformed into plane array which composed by metasurface.And then this method applied to complex models,the simulation results show that the metasurface array has similar RCS scattering characteristics with the 3D structure.4.The technology of metasurface lens and the metasurface absorbers are applied to the nonreciprocal devices researching with plane wave.By using the deflection of the lens and the absorption of the absorbing materials,one direction of the propagation system is studied.