Self-isolated miniaturized four-port multiband 5G sub 6 GHz MIMO antenna exclusively for n77/n78 & n79 wireless band applications

This paper reports a novel four-port multiband MIMO antenna technology radiating electromagnetic energy which is designed and fabricated on FR4 substrate for n77/n78 and n79 bands which are implemented for mobile users with compact dimensions of 0.997λ 0 × 0.997λ 0 (λ 0 at 3.25 GHz) mm 2 . The miniaturization of the design utilizes a square slotted substrate with an additional four circular-rectangular dielectric for EM wave propagation. The top plane of the substrate is utilized with a printed circular patch which is also etched with five-star-fractal geometry and is connected to a microstrip feed line. The bottom plane corresponds to the partial ground which is chamfered at the edges. Also, a circular parasitic structure is placed beneath the radiating patch. The complete structure forms 4-port MIMO configuration covering bandwidth of 3.25–3.90 GHz (n77/n78: S (11max) = − 24.52 dB at 3.55 GHz) and 4.37–4.95 GHz (n79: S 11(max) = − 19.79 dB at 4.51 GHz). The simulated and measured results extracted from the simulator, equivalent circuit model, and developed prototype are in good agreement. The MIMO antenna offers good radiation patterns in both principal planes with reduced cross-polarizations. The exceptional diversity performance including ECC (4 × 4) < 0.005, DG (4 × 4) ≈ 10.0 dB, TARC (4 × 4) < − 10.0 dB, CCL (4 × 4) < 0.0052 b/s/Hz and MEG (4 × 4) ≈ − 3.08 dB suggest the MIMO antenna is viable for 5G-Sub 6 GHz applications.