The Study Of Terahetz Polarization Control Devices Based On Composite Metasurface

With the advent of 5G,the importance of wireless communication technology in various fields has become more and more obvious.People hope to achieve higher requirements for the regulation of electromagnetic waves,the control of electromagnetic wave polarization is a hot topic in the international discussion.Due to the limitation of the size of the material,the difficulty of processing and the loss of work,the traditional polarization control devices cannot be well applied in the terahertz frequency band.Metasurface is a special metamaterial.It is a microstructure of artificially designed subwavelength scattering units,through the metal-mediμm structure of array configuration implementation regulation of electromagnetic waves,its electromagnetic properties reference the theory of metamaterials,but more powerful than a metamaterial function,and simple preparation,low loss,its outstanding advantages,so more suitable for the large-scale applications.In this paper,a polarization control device by a composite metasurface structure is designed based on reflective metasurfaces,which has the advantages of ultra-wide band and high quality polarization conversion performance.In addition,based on the current characteristics of Schottky diode,a dynamic polarization control device is proposed to realize the dynamic regulation of the polarization performance of the polarizer in the ultra-wide band.Finally,a Radar Cross Section(RCS)coding sequence based on the composite metasurface polarization control device is proposed,and its RCS reduction effect is outstanding.The main work of this paper is as follows:Based on the results of double parallel lines super surface polarization structure,in this paper,Compared with a metal or periodic dielectric structure,the bandwidth of the composite metasurface polarization conversion device is developed obviously.The performance is improved,and broadband and high-efficiency polarization conversion are achieved.In this paper,a dynamic polarization structure with Schottky diode integrated into the metasurface is designed.The free conversion between polarized mode and nonpolarized mode of the dynamic polarized metasurface is realized by using the loading of Schottky diode.In the polarization mode,the polarization conversion of ultra-wideband can be realized.There is almost no polarization phenomenon in the non-polarization mode.For composite metasurface polarization structure,a new RCS coding sequence is proposed.After the coding method is applied to the composite metasurface polarizer unit,the electromagnetic wave incident on the metasurface can be emitted in the form of a lot of scattered waves.Therefore,the incident energy will be dispersed to each beam.In the frequency range of 120GHz-330 GHz,the RCS reduction has exceeded 20 dB,and the maximμm reduction has reached 30.9dB,achieving an excellent RCS reduction.