Lotus flower-shaped 4/8-element MIMO antenna for 5G n77 and n78 band applications

Abstract

This paper reports a 4 × 4 and 8 × 8 MIMO antenna configuration on FR4 substrate occupying the area of 1.43λ o × 1.43λ o mm2 (f = 3.58 GHz) and 2.14λ o × 2.14λ o mm2 (f = 3.50 GHz). The proposed design is exclusively developed for 5G: n77/n78 wireless band applications. The MIMO antenna comprises of Lotus-shaped radiating element with DGS (defected-ground-structure) in-ground and the addition of slits providing boresight radiation. All the radiating elements are placed orthogonally in a 4 × 4 configuration while pairs of antennas are also placed in the same fashion for 8 × 8 MIMO antenna configuration. The high isolation of more than 16 dB is achieved by using a novel decoupling structure in the ground. Also, the MIMO antenna are characterized with diversity performance including ECC, DG, TARC, CCL and MEG achieving permissible values of <0.005, ∼10 dB, <0 dB, <0.10b/s/Hz and ∼ −3 dB respectively. The peak gain corresponds to 4.51 and 5.02 dBi with radiation efficiency of more than 80% for 4 × 4/8 × 8 MIMO antenna configuration. The proposed antenna also offers desired 2D radiation patterns in principal planes.