This paper proposes a novel low-profile structure of graphene-based sub-THz reconfigurable phased array antenna for versatile beam steering function. The model is composed of a pair of dipole antenna coupled symmetrically to the feed point through co-planar strip-line (CPS) and two graphene sheets loaded at the lower boundary of the CPS. To exploit beam steering capability, the chemical potential of each sheet is tuned independently by applying two adequate DC biasing voltages. Along with its simplicity, the proposed model enables versatile beam steering via a narrow tuning range of chemical potential, therefore, promoting for easy implementation through the common available micro-fabrication techniques. Through simulating the model at the D-band, it is shown that beam steering of can be achieved at 150 GHz in the E-plane with a chemical potential that varies from 0 to 0.2 eV. Due to the low-profile design and narrow chemical potential range, the proposed model is potentially promising to be applicable at higher frequencies up to visible band.