This paper introduces an innovative 2×2 MIMO, Multi-Input Multi-Output, antenna working in the sub-Terahertz (THz) band for 6G, 6-Generation, communications (0.1–1.2 THz). This antenna was designed with main metal octagonal patches and parasitic graphene elements, providing pattern reconfigurable antenna for Single-Input Single-Output (SISO) andMIMOapplications. In the YZplane, aforementioned antenna illustrates a tunable pattern (0°,+70°,−70°) for SISO in three distinct states. In the XZ-plane, it obtains a versatileMIMOfunction with a controllable pattern (0°,±20°, ±45°,±75°) across four states, simultaneously. The adaptability of the radiation pattern is originated from changing graphene conductivity through biasing. In addition, a graphene metasurface was applied as an absorber, moderately improving isolation between 2 antenna elements, minimizing interference, and enhancing the overall system capability. The proposed schematization achieves a significant isolation up to−35 dB within theMIMOantenna’s operational frequency band. Moreover, theMIMOantenna touches amaximumgain of 9.5dBi, maximumimpedance bandwidth of approximately 91%during different states, 10dBi DiversityGain, and 2.62 ´ 10-7 ECCin the resonance frequency, which demonstrates novelty designing, remarkable pros, and broad applications in the landscape evolution of 6G communication networks.
