▎ 摘　　要

In this paper, a new method for the design of pixelated graphene-based coding metasurface is proposed. This method suggests a straightforward approach by utilizing graphene tunable pixels (GTPs), which can control the reflection phase in a real-time manner at terahertz (THz) frequencies. The proposed unit cell is composed of four distinct graphene patches in the same layer, which has a separate DC bias source. Each meta-atom can change the reflection phase by choosing appropriate chemical potential that obtained by utilizing optimization-based methods. By changing the reflection phase profile across the metasurface, the proposed device can manipulate the reflected wave dynamically. To investigate our proposed structure, we present a multifunctional reconfigurable metasurface to manipulate electromagnetic ( EM) wave in the half-space and generate converged vortex beam, non-diffractive Bessel beam, and EM bump illusion. The simulation and theoretical results show that the suggested method offers a feasible strategy for multifunctional metasurface applications. Chemical potential optimization method in graphene-based coding metasurface is not limited to a specific structure for phase-only metasurface. Indeed it has an unique capability for phase, amplitude, and polarization control in various beamforming applications at THz spectrum for modern information systems, data encryption, and THz communication applications.