Single split-ring resonator loaded self-decoupled dual-polarized MIMO antenna for mid-band 5G and C-band applications

This paper presents the design and development of a dual-band and dual-polarized two-port multiple-input-multiple-output (MIMO) antenna for mid-band 5G (3.4-3.6 GHz), and C-band (4-8 GHz) applications. The antenna design is very simple and it mainly consists of a circular-shaped single split-ring resonator on the top side of the substrate which is coupled with the microstrip line feed line. The bottom side is comprised of a rectangular-shaped defected ground structure. Due to this dual-band response is obtained and the first band shows linear polarization and the second band provides circular polarization. The entire dimensions of the intended two-port MIMO antenna are 46 mm x 21 mm x 1.6 mm. The antenna measured results offer a wider impedance bandwidth (IBW) of 20.22% and 44.07% for the two bands centered at 3.54 GHz and 6.33 GHz respectively. Also, the proposed MIMO antenna shows minimum isolation of 15 dB for the two frequency bands with a smaller edge-to-edge spacing of 4 mm (0.04 lambda(0)) between the two antenna elements. Moreover, the second band provides an axial ratio bandwidth of 3.97% centered at 6.78 GHz. The antenna shows excellent IBW, good isolation between the single antenna elements without the use of any decoupling mechanism, better antenna gain, and improved envelope correlation coefficient by maintaining smaller antenna size compared to similar types of existing two-port MIMO antennas in literature. (C) 2020 Elsevier GmbH. All rights reserved.