Research On An On-chip Periodic Terahertz Modulator

Terahertz communication is a key technical means of high-speed spatial information transmission in the future.It has the advantages of large capacity,high transmission rate,strong anti-interference ability and good security.How to realize efficient and fast modulation of terahertz wave has become a hot topic in recent years.he combination of artificial microstructures with semiconductors,two-dimensional electronic gas,superconductors,graphene and other materials to realize the dynamic control of terahertz wave brings great opportunities for the development of THz modulator.On this basis,this paper will combine artificial microstructures with VO₂,HEMT and terahertz schottky diodes to realize dynamic control of terahertz waves,and the design of THz modulator with low insertion loss,high modulation depth and high rate is the main research content of this thesis.This article focuses on terahertz direct modulation technology.With the combination of artificial microstructure,VO₂,HEMT,and terahertz Schottky diodes,this paper studies and designs a variety of different terahertz direct modulators working at 0.34THz.The terahertz communication link at 0.34THz has been tested for eye diagrams up to 4Gbps,specifically:1.Firstly,the control mechanism of artificial microstructure and SSPPs on terahertz wave is analyzed.By defining the VO₂ material model in CST Microwave Studio,and studying the resonance characteristics of the microstructure,it is found that the direct control of terahertz wave can be realized through the phase transition properties of VO₂.2.Two waveguide-loaded terahertz modulators are designed.Firstly,the unilateral fin line was selected as the basic transmission line,and the electromagnetic characteristics of HEMT were controlled by applied voltage to change the electromagnetic resonance mode in the artificial electromagnetic resonance structure.In this way,the terahertz wave propagated in the fin line waveguide was modulated,and a terahertz amplitude modulator with artificial micro-structure nested in the fin line was realized.Then,a design method of external loaded tunable metal wire terahertz direct modulator is provided to realize amplitude modulation of terahertz wave outside the waveguide by controlling the electromagnetic characteristics of Schottky diode by electric applied voltage.3.The processed terahertz dynamic device was tested in detail,and a terahertz communication experimental system was set up at a working frequency of 0.34THz.The modulation capabilities of dynamic devices under sinusoidal signals and high-speed baseband signals were tested separately.The sinusoidal signal test shows that the highest response rate of the device can reach 13GHz,and the eye diagram test shows that the actual data transmission capacity of the device reaches 4Gbps.Through the research of the above three parts,this paper analyzes and discusses terahertz dynamic devices in detail from design simulation and processing tests,and verifies the superiority of direct modulation technology in terahertz communication systems.It provides key technical means for the development of future space communication systems.