DNG metasurface-assisted quad-port silicon–graphene-built MIMO antenna offering high gain and circular polarization in the THz band

The design and analysis of a quad-terminal graphene-ceramic radiator functioning in the THz domain are presented in this study. The hybrid mode (<i>H</i><i>E</i><i>M</i>_11<i>δ</i>) inside the silicon ceramic is stimulated by means of an asymmetrical fan-formed slot. This slot shape creates the circular field in between 3.5 and 4.1 GHz. A metasurface (MS) suspended over a two-terminal radiator enhances the gain within the working regime, i.e., 11.0 dBi. The polarization and space diversity concept improves terminal-to-terminal isolation above 30 dB. As confirmed by CST electromagnetic simulations, the radiator can function throughout 3.25-4.15 THz. Frequency tunability is provided by the graphene covering on the dielectric. The antenna's diversity gain (DG) is around 9.9 dB, and its envelope correlation coefficient (ECC) is less than 0.01. The suggested MIMO radiator is a viable option for THz-enabled 6G wireless communication systems because of its high gain and steady far-field performance.