Design And Analysis Of Reconfigurable Terahertz Arrays

Electromagnetic metamaterials have special electromagnetic properties not found in natural materials,and their electromagnetic parameters such as permittivity and permeability can be changed by altering the "atom" structure,so they are of great value in the fields of electromagnetic stealth,blackbody radiation,superlenses,and antennas.And they have become a research hotspot in fields such as electrical engineering.Terahertz waves have also been greatly developed in recent years due to their special properties such as safety,high transmittance,and high resolution.Meanwhile,graphene has been widely used in new energy and reconfigurable communication devices because of its excellent physical properties.In this paper,based on the theory and design methods of metamaterials,the electrically tunable properties of graphene are used in the terahertz band to design metamaterial array devices that can achieve two different functions of beam deflection and wave absorption,and their electromagnetic performance are studied.Firstly,a terahertz reflectarray antenna with reconfigurable radiation direction is designed.For TE polarized electromagnetic waves,a phase range of 360° is achieved by varying the graphene chemical potential from 0 eV to 1.8 eV with a minimum amplitude of-5.6 dB.Based on the phase response,four different beam deflection modes of-10.2°,-20.8°,-32.3°,and-45.5° were realized by precisely programming each electrode connected to the graphene patch.Secondly,a switchable reflectarray antenna is proposed,which consists of crossed metal dipoles mounted on a graphene grid to enable the switching of radiation patterns at 1 THz.The simulated phase response results show that a phase range of more than 330° can be obtained when the size of the metal dipole is gradually increased from 11 ?m to 70 ?m.The simulated field distributions and radiation patterns show that when the structure is in a specific bias state,it can deflect the incident vertical plane wave in a pre-designed direction.A reconfigurable dual-band metamaterial absorber is proposed.The absorber achieved a dual-band absorption curve with three resonant peaks.When the graphene chemical potential is 1 e V,the absorber achieves more than 90% absorption in the frequency bands of 1.28 THz-1.4 THz and 7.33 THz-8.74 THz.When the graphene potential gradually decreases to 0 e V,the absorption peak in the frequency band of1.28 THz-1.4 THz is red-shifted and the absorption amplitude gradually decreases.The absorption curves in the frequency band of 7.33 THz-8.74 THz remain relatively stable.In this thesis,the reflectarray antennas and metamaterial absorbers are simulated,and the results confirm their potential value in practical engineering applications,which lays a foundation for future work and provides a certain reference significance.