Broadband and Compact Circularly Polarized MIMO Antenna With Concentric Rings and Oval Slots for 5G Application

A broadband and compact size circularly polarized (CP) two-port multiple input output (MIMO) antenna with a footprint of 25 mm $\times20$ is investigated. The designed oval-shaped MIMO employs concentric rings oval slots (CROS), along circular radiator two open-ended parallel protruded stubs. CP radiation achieved by embedding three slots, in which them are deployed at the left right side rings, whereas third one top section rings. measured 10-dB impedance bandwidth proposed was 46.30% (3.12–5.00 GHz), its corresponding 3-dB axial ratio (ARBW) 41.34% (3.30–5.02 GHz). Furthermore, very wide beamwidths notation="LaTeX">$137^{\circ }\pm 0.2$ notation="LaTeX">$154^{\circ were right-hand polarization (RHCP) left-hand (LHCP) patterns, respectively. minimum isolation between elements 18.50 dB without using any additional decoupling structure, calculated envelope correlation coefficient (ECC) < 0.03.