Manipulation And Application Of Metamaterials To Electromagnetic Waves

Electromagnetic technology involves all aspects of life.It brings convenience to people,but also causes many adverse effects such as electromagnetic leakage,electromagnetic interference and so on.At the same time,with the trend of miniaturization and integration of electronic and communication equipment,the traditional electromagnetic control technology has been unable to meet the comprehensive challenges of smart,light,wide and strong.Because of its special electromagnetic characteristics,that is,some natural materials or traditional materials do not have special electromagnetic characteristics,electromagnetic metamaterials provide new theoretical support and thinking direction for electromagnetic absorbing and stealth technology,so it is worth our in-depth study.This paper starts from integration and miniaturization.In order to solve the problems of electromagnetic protection,electromagnetic stealth and shortwave electromagnetic interference,metamaterial absorber,codding metamaterial and electromagnetic induced transparent radome are designed respectively.This paper mainly completes the following work:1.A metamaterial absorber is designed by loading lumped elements.The structure overcomes the problem of narrow absorption bandwidth of metamaterial absorber.In addition,the integrated design of matching layer and absorbing layer is achieved.It breaks through the limitation that the thickness of traditional absorber should meet the wavelength of ? / 4(at resonance frequency),and the thickness is 2.64 mm(0.07 lambda).The absorptivity of the microwave absorber is more than 90% in the working bandwidth of 8-18 GHz.2.According to the principle of inverse phase cancellation,the incident electromagnetic wave is diverged to all directions through the arrangement and combination of digital units to reduce the radar cross section(RCS).In this paper,the simulated annealing algorithm is used to optimize the coding array,and a coding metamaterial is designed.The structure can work steadily from 7GHz to 14.6 GHz,and the RCS can be reduced by more than 90%.In addition,the structure has polarization-independent characteristics and can work on different materials.The test results and simulation results of the coding metamaterial show that they are in good agreement within the allowable range of errors.3.The realization of miniaturization at low frequency is studied,and a metamaterial is proposed for this purpose in MHz band.Two square rectangular coils in reverse series are used to increase the equivalent inductance of the metamaterial.The application of high dielectric constant dielectric substrates can further reduce the resonance frequency.Finally,a metamaterial working at 14.08 MHz is realized in the planar structure.The structure has a high Q value,and the electric field energy can be amplified 85 times in resonance.In addition,three kinds of EITlike generation methods are introduced.Based on the above-mentioned metamaterials,an EITlike metamaterial is designed by using the bright-dark mode.The structure works at 14.38 MHz and has a high Q value.It can effectively reduce the Joule heat loss and radiation loss.