Research On Terahertz Functional Devices Based On MEMS Planar Reconstruction Of Tunable Metamaterials

Terahertz waves have broad application prospects in the fields of biomedical imaging,environmental monitoring,chemical analysis,and communications due to their transient,high penetration,and safety characteristics.However,the interaction between most materials in nature and terahertz waves is very weak,and the transmission and radiation of terahertz waves cannot be effectively achieved.As a result,the development of terahertz technology and its functional devices has been seriously hindered.In recent years,the realization of THz functional devices by tunable metamaterials has attracted widespread attention.However,the tuning ability of the traditional active material-based tuning method obviously depends on the nonlinear characteristics of the material,resulting in a limited tuning range,which is not conducive to practical applications;the tuning ability based on the structure of the non-planar microelectromechanical system depends on the cantilever arm warpage height,resulting in The tuning range of the device is limited,the process is complex and the reliability is low.Therefore,this paper proposes three tunable terahertz metamaterial structures based on micro-electromechanical system(MEMS)planar reconstruction for these drawbacks,and realizes a variety of large-scale,multi-functional,real-time dynamic tunable terahertz functional devices.The main research contents are as follows:1.This thesis first proposes a terahertz metamaterial frequency selector based on MEMS planar reconstruction,which uses electrostatic micromechanical drivers to bidirectionally drive a movable "T" structure and a fixed "T" structure to achieve front contact,mutual separation and back contact State to form an "H" type structural unit or a "ten" type structural unit.The research results show that during the translation of the movable “T” structure,the electromagnetic coupling strength changes,and the total effective capacitance changes,causing the transmission resonance frequency to shift,thereby achieving its frequency tunability.In addition,in frontal contact and In the back contact state,the reconfigurable metamaterial can realize the transition between polarization-dependent and polarization-independent states for different polarization states.2.Designed a terahertz metamaterial converter with switchable ring and galvanic couplers based on MEMS plane reconstruction.The metamaterial structure is composed of two "E" type arrays.The plane translation of the micromechanical structure is driven by static electricity to change the two The spacing of the "E" structure array realizes the switching between ring dipole resonance and electric dipole resonance.In addition,under TE and TM polarization,both single-mode resonance and dual-mode resonance can be converted.3.Proposed and constructed a digital logic functional device based on MEMS planar reconstruction tunable terahertz metamaterial.The metamaterial structure is composed of a double-layer movable split ring array,and the digital signal is simulated by applying voltage to the upper and lower comb drivers respectively.For the input of "1" and "0",the output state uses the transmission spectrum with or without resonance to simulate the output of "1" and "0",and realizes the multi-input and output XOR gate logic function.