▎ 摘　　要

We perform mathematical modeling of diffraction of plane electromagnetic waves by multilayer metasurfaces comprised by elements of graphene nanoribbons. The modeling is based on solving the three-dimensional boundary value diffraction problem by three methods, specifically, those of self-contained units with Floquet channels, the volume integro-differential equation, and approximate boundary conditions. The coefficients of reflection, transmission, and absorption of s- and p-polarized waves by metasurfaces made of elements of rectangular graphene nanoribbons are calculated as functions of the frequency and the incidence angle for various values of the chemical potential with allowance for the geometric and dimensional effects in the terahertz frequency band. It is shown that at the resonant frequencies of the surface plasmon polariton, multilayer metasurfaces comprised by two graphene strips in an elementary cell on substrates, which contain layers of a dielectric and graphene, are electrically controlled efficient wideband terahertz absorbers and polarizers in the reflection regime that are insensitive to incidence angles.