Terahertz Shielding Effectiveness of Graphene-Based Multilayer Screens Controlled by Electric Field Bias in a Reverberating Environment

Innovative multilayered screens made of laminated graphene sheets, with SiO₂ as interlayer, over a glass substrate are proposed as electrically-tunable electromagnetic shields at terahertz. The shielding effectiveness (SE) modeling is developed applying the transmission line method in a reverberating environment (i.e., with the screen surface illuminated by an infinite set of plane waves impinging with all possible propagation directions), which is of particular relevance in electromagnetic compatibility (EMC) studies. A new equivalent single layer (ESL) model of the graphene/SiO₂ laminate (GL) is also proposed in order to provide a simple computationally-efficient method for the EMC design of GL shielding configuration via numerical EM tools. The approximate model is validated by comparison with the results obtained applying the exact one. The sensitivity analysis of the SE in reverberating environment is performed in the frequency range up to several tens of terahertz with respect to: the electric field bias of the graphene sheets, affecting their chemical potential level through an electrostatic carrier doping; the relaxation time characterizing the electron transport in graphene; the thickness of the SiO₂ interlayers. Finally, the SE computed for different shielding configurations against a plane wave with normal or oblique incidence is compared with the one obtained in a reverberating environment in order to highlight the most significant differences at terahertz frequencies.