| By effectively utilizing the resonance characteristics of electric and magnetic dipoles,people can achieve more advanced metasurface design processes,broaden the adjustment range of metasurface parameters,and achieve more accurate electromagnetic wave regulation.In recent years,an artificial electromagnetic surface-Huygens’ metasurface-designed based on Huygens’ theory and utilizing the aforementioned resonance characteristics has been proposed.The theoretical loss of this metasurface is0,and it has high transmittance,which can effectively improve work efficiency.In recent years,it has attracted the attention of researchers.People have achieved many novel electromagnetic wave modulation functions based on Huygens’ metasurfaces,such as holographic imaging,metalenses,and so on.However,at present,Huygens’ metasurfaces only consider spatial dimensional light field regulation and do not explore temporal dimensional light field regulation,so they are still constrained by the Lorentz reciprocity theorem.At the same time,these metasurfaces have complex structures(structural units constructed by independent electric and magnetic dipole resonance structures),high manufacturing costs,and are difficult to adapt to complex environments,seriously restricting their practical applications.Based on this,the innovative research in this thesis has constructed two time-varying Huygens’ metasurfaces that do not require independent magnetic dipole components,but instead transforms the magnetic dipole and electric dipole into superlattice,which will undoubtedly greatly promote the development of Huygens’ metasurface,and is of great significance to the research of transmission time-varying metasurface.The main innovative research results of this thesis are as follows:(1)A study was conducted on active and time-varying induced magnetic Huygens’ metasurfaces,and the regulatory mechanisms of two types of metasurfaces on electromagnetic waves in both spatial and temporal dimensions were obtained.Design ideas were proposed.A transmission dynamically adjustable cylindrical metalens based on actively induced magnetic Huygens’ metasurface was designed.The metalens can dynamically adjust the spatial phase distribution by adjusting the voltage to achieve dynamic control of the focusing effect.These two types of induced magnetic Huygens’ metasurfaces have great application value in fields such as radar and imaging.(2)Based on the electromagnetic wave regulation mechanism of time-varying induced magnetic Huygens’ metasurface,a Doppler stealth cloak based on time-varying induced magnetic Huygens’ metasurface was studied and designed.The basic theory of achieving Doppler stealth has been derived,and a design method for a time-varying induced magnetic Huygens’ metasurface that can achieve Doppler stealth has been proposed.Through the time-varying mechanism,the system regulates the feeding of the metasurface to generate linear phase in the time domain,thereby generating frequency shift to compensate for the Doppler effect caused by object motion and achieving stealth effect.This method provides new theoretical guidance for the precise regulation of the electromagnetic wave spectrum on the Huygens’ metasurface,and also lays a theoretical foundation for the efficient conversion of time-varying induced magnetic Huygens’ metasurface beams.(3)A high-efficiency method for electromagnetic harmonic conversion and deflection based on time-varying induced magnetic Huygens’ metasurface has been proposed in the study.Firstly,the efficient conversion of electromagnetic wave harmonics and the mechanism and method of beam deflection were studied.Theoretical research shows that this method can achieve 100% conversion efficiency of electromagnetic harmonics.Subsequently,a time-varying induced magnetic Huygens’ metasurface was designed that can achieve efficient conversion and deflection of electromagnetic harmonics.Research has shown that this metasurface can regulate the transmission phase within a range of nearly 360°,achieving an energy conversion efficiency of 80% and a deflection scattering angle of nearly 70°.This study will provide a new development approach for the next generation of wireless communication systems. |
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