A wideband high-isolation four-port MIMO antenna with orthogonal diversity and DGS for 5G sub-6 GHz applications

Abstract

The 5G NR sub-6 GHz bands n77 (3.3–4.2 GHz) and n78 (3.3–3.8 GHz) are widely used for modern 5G communication systems due to their balanced coverage and capacity. This work presents a compact wideband four-port MIMO antenna employing orthogonal diversity and defected ground structure (DGS) techniques for 5G sub-6 GHz applications. The proposed design consists of four orthogonally arranged C-shaped hexagonal patch antennas printed on a 40 × 40 × 0.8 mm³ FR4 substrate. The antenna achieves an impedance bandwidth of 3.3–3.8 GHz with an approximate fractional bandwidth of 14.1%. Microstrip line feeding is used to improve impedance matching. The fabricated prototype shows good agreement between simulated and measured results, exhibiting wide bandwidth, low mutual coupling, and stable radiation characteristics. Furthermore, important MIMO performance parameters such as ECC, DG, MEG, CCL, and TARC satisfy acceptable diversity performance requirements, making the proposed antenna suitable for compact 5G sub-6 GHz wireless applications.