▎ 摘　　要

A graphene-based reflectarray antenna operating at 1.6 THz is introduced in this paper. This reflectarray has dimensions of 20 lambda x 20 lambda (3.75 mm x 3.75 mm) containing 40 x 40 (1600) cells. The dimensions of each cell are lambda/2 x lambda/2. Three different hexagonal-shaped unit cells are analyzed for the appropriate design. Reflection coefficient phase ranges for the three unit cells are 0 degrees-190 degrees, 0 degrees-225 degrees and 0 degrees-525 degrees, respectively. The unit cell (uc 3 ), which gives the reflection phase of 525 degrees, is chosen to construct the reflectarray antenna. The array cells are placed upon a silicon dioxide (SiO2) substrate. The feed is a horn antenna positioned at the focal point. The focal-length-to-diameter (F/D) ratio is one. The proposed reflectarray antenna is analyzed using the finite integration technique. Different unit cell sizes are used to compensate for the phase of the different path lengths. Maximum gains of 18.7, 19, and 17.7 dB are obtained at 1.5, 1.6, and 1.7 THz, respectively. In terms of the number of elements, the proposed structure has a very good gain.