Dual polarized firelight-shaped 4 Port MIMO antenna using connected defected ground for 5G Sub-6 GHz applications

Abstract A compact 5 G sub-6 GHz 4-port dual polarized MIMO antenna has been developed to meet modern wireless demands in smart cities. The MIMO system consists of four identical elements in a mirrored arrangement within a compact (50 × 50.415 × 1.6 mm 3 ) design. It achieves a -10 dB bandwidth of 3.17–5.36 GHz (fractional BW:51.35%), covering 5G sub-6 GHz bands n77 (3.30–4.20 GHz), n78 (3.30–3.80 GHz), and n79 (4.40–5.0 GHz). The 3 dB axial ratio bandwidth (3.37–3.94 GHz) supports full n78 and partial n77 bands. The isolation of the antenna is improved by offset shift of patch. The antenna attains a peak gain of 7.20 dBi, with S 11 and isolation below −10 dB and −15 dB, respectively. Diversity metrics include TARC < −10 dB, ECC < 0.014, DG ≈ 10 dB, MEG<−3 dB, and CCL < 0.5 bits/s/Hz over 3.34–5.06 GHz. The design is validated using an ANRITSU MS46122B VNA and a 43 GHz anechoic chamber, demonstrating excellent agreement between measured and simulated S-parameters and radiation patterns. The proposed antenna is circularly polarized with 3 dB axial ratio bandwidth (ARBW) from 3.37–3.94 GHz, and linearly polarized in the other part of the specified bandwidth. The proposed MIMO antenna is a strong candidate for future 5G applications.