This work has proposed an orthogonal dual cavity quarter mode substrate integrated waveguide (QMSIW) MIMO antenna resonant at 4.751 GHz frequency. This innovative design features two rectangular QMSIW cavities, sharing a common boundary defined by vias, with feed placement positioned at 180° relative to the other. Each cavity of the MIMO antenna has an electrical dimension of 0.25λ0 \(\times \) 0.24λ0, optimizing its performance while providing high isolation between both cavities. The S12 parameters at − 14.5 dB along with the corresponding S21 parameters also measured at – 14.5 dB for the MIMO antenna, ensure a high level of isolation between the antenna ports. The antenna exhibits an envelope correlation coefficient (ECC) of 1.1 \(\times \) 10-4 value, indicating excellent diversity performance with a diversity gain of 9.9 dB. Moreover, the antenna achieved a gain of 5.71 dB and a fractional bandwidth of 2.95%. Further, this prototype is etched on RT duroid substrate. The fabricated results validate the simulation work, accounting for acceptable fabrication losses. The proposed MIMO is apt for deployment within the NR FR-1 5G frequency band.
