Design and optimization of micro-sized wideband fractal MIMO antenna based on characteristic analysis of graphene for terahertz applications

In this article, an optimized, highly efficient, wideband 1 × 2 Multiple-Input-Multiple-Output (MIMO) fractal antenna is designed for high-speed short-range communication, video rate imaging, medical imaging, and explosive detection in the terahertz frequency band. The suggested fractal THz MIMO antenna configuration is originated from basic rectangular patch antenna through several design iteration steps with partial ground plane structure. A polyimide substrate of thickness 45 µm and dielectric constant of ε_r = 3.5 is utilized for designing the proposed fractal antenna. The performance of the proposed antenna is enhanced using particle swarm optimization (PSO) technique. The required antenna characteristic parameters like radiation pattern, reflection and transmission coefficient, gain, efficiency, directivity and diversity parameters like channel capacity, envelope correlation coefficient, total active reflection coefficient and mean effective gain are computed using computer simulation software (CST). The effect of chemical potential (μ_c) of the graphene material is also analyzed and discussed. The designed MIMO antenna covers a wider impedance bandwidth of 400 GHz (0.35–0.75 THz) with coaxial feeding. For the designed MIMO, the patch elements maintain isolation of ≤ − 25 dB throughout the entire operating band. The designed fractal-based MIMO antenna could be a promising choice for the upcoming terahertz applications due to its good impedance, radiation and diversity performance parameters.