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Title: Modelling and design of graphene-based THz devices
Author: Yang, Liang
ISNI:       0000 0004 7962 5029
Awarding Body: Queen Mary, University of London
Current Institution: Queen Mary, University of London
Date of Award: 2019
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In recent years, terahertz (THz) frequency band has gained great interest of researchers in a number of fields due to attractive THz applications such as wireless communications, remote sensing and imaging. Graphene, a two-dimensional carbon material with extraordinary properties in the THz spectrum, has been considered as a promising candidate for novel THz devices to achieve these valuable applications. As related modelling methods are indispensable, this thesis summarises my PhD work on the development of novel numerical methods for graphene-based THz devices. In the THz spectrum, both electrostatic bias and magnetostatic bias can change the conductivity of graphene. A finite-difference time-domain (FDTD) modelling based on auxiliary element method is proposed for the tunable linear responses of graphene. Moreover, graphene has nonlinear responses under strong THz radiation. A novel FDTD method, which is based on a J E characteristic formula, is proposed for modelling the nonlinear electrodynamic responses of graphene in the THz spectrum. FDTD results of linear responses are in agreement with theoretical and measurement results in the published literature. Nonlinear FDTD results successfully demonstrate nonlinear phenomena including odd-harmonic generations and frequency-mixing effects. The proposed FDTD modelling methods can be used as full-wave design tools for graphene-based devices. In addition, the FDTD modelling methods are utilised in the design of electrically tunable graphene-based reflectarray antennas and magnetically tunable graphene-based reflectors. Regarding the tunable reflectors, their performance has been experimentally explored and discussed. In addition, a modified equivalent circuit modelling is developed to extract the parameters of graphene from measurement data.
Supervisor: Not available Sponsor: China Scholarship Council (CSC)
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available