This paper presents a graphene-based antenna array for terahertz (THz) applications. The suggested antenna array has four radiating square shaped patches fed by a coplanar waveguide (CPW) technique. The proposed antenna array operates at the three frequencies with operational bandwidths of 1.173-1.210 THz (at 1.19 THz), 1.270-1.320 THz (at 1.3 GHz), and 1.368-1.346 THz (at 1.4 GHz). The total area of the antenna array is reported as 1000 × 1000 μm2, printed on a Silicon substrate with a thickness of 20 μm and a dielectric constant of ϵ r = 11.9. To enhance the structure's performance and optimize the feeding network, a parametric analysis was performed using the FDTD technique. Furthermore, the key properties of the proposed antenna array, such as resonance frequency, peak gain, and radiation efficiency, may be changed by adjusting the chemical potentials of the graphene in the antenna array. The use of graphene's chemical potential tuneability yields exceptional results comparing to the recent research outputs, with a peak gain and radiation efficiency of 10.45 dB and 70%, respectively. These results show the performance of the suggested design for constructing antenna arrays for use in THz applications.