Comparative Design and Performance Analysis of Multiband MIMO Antenna for Sub-6 GHz 5G Network

This paper presents the design and performance comparison of a multiband dual diversity 8-element multiple-input multiple-output (MIMO) antenna with a 4-element MIMO antenna with defected ground structure (DGS) at 2.45/3.5/5.2/6 GHz. The proposed antennas were designed on a flame retardant (FR-4) having a dielectric constant of 4.4 , (\(\varepsilon\)r =4.4), dimensions of 200x200x1.6 mm 140x90x1.6 mm  respectively. The antennas were simulated and analyzed using Computer Simulation Studio (CST Studio). Results obtained from the simulation showed that the 8-element MIMO antenna achieved a combined bandwidth of 908.68 MHz. In contrast, the 4-element MIMO antenna with DGS achieved 4.22 GHz bandwidth on average. Broadside radiation pattern was observed across the three frequency bands in both E- and H-plane with an average main lobe magnitude of 7.8 dBi. Furthermore, the proposed antennas achieved consistent Envelop Correlation Coefficient (ECC) and Diversity Gain (DG) values of 0.0008 and 9.999 and Port-to-port isolation of 27 dB across all frequencies considered. Also, an antenna gain of 8.58 dB was achieved at a frequency of 6 GHz for the 8-element MIMO antenna, while a maximum gain of 5.58 dBi was achieved by the 4-element MIMO antenna with DGS. The gain, isolation, DG, and ECC between adjacent ports and the loss in capacity were within the standard margins, making the antenna structure suitable for MIMO applications.