Modified ground and slotted MIMO antennas for 5G sub-6 GHz frequency bands

Abstract

Abstract Multiple input multiple output (MIMO) systems, which use multiple antennas to deliver faster data rates, are one of the promising methods in 5G services. 5G is a popular issue among the world's main telecom firms currently. The sub-6 GHz band for 5G applications in various countries lies between 3 and 5 GHz. The sub-6 GHz 5G bands are 3.4–3.8 GHz in Europe, 3.1–3.55 GHz in the USA, and 3.3–3.6 GHz and 4.8–4.99 GHz in China. This paper presents a two-element slotted octagon-shaped antenna operating in the sub-6 GHz band (3.1–4.5 GHz) for 5G applications. A T-formed isolation structure is placed at a ground plane to minimize mutual coupling between MIMO antennas. The proposed MIMO antenna has physical dimensions of 55 × 38 mm2 and an envelope correlation coefficient or correlation of 0.0004 over the entire operating band. The antenna operates at 3.6 GHz, with a return loss of 40.8 dB at the resonance. An antenna prototype has been investigated and proven to be of excellent quality in terms of performance like isolation >20 dB, efficiency >80%, and mean effective gain <−3 dB over the full operating band.