Edge Hole Effect on Isolation of UWB MIMO RDRA for 5G Outdoor Applications

- For 5G sub-6 GHz outdoor applications, a highly isolated two-port rectangular dielectric resonator antenna (RDRA) with UWB MIMO is presented in this research. For isolation enhancement purposes at the lower frequency band (2.27 GHz-2.62 GHz), a longitudinal slot is inserted at the ground plane. For isolation enhancement at the higher frequency band (3.9 GHz-5.73 GHz), an edged hole is inserted in the RDRA. Investigations are conducted on the impacts of slotted ground as well as edged hole radius on isolation. The orthogonal feeding scheme of UWB MIMO RDRA considering both edged hole and slotted ground plane effects are investigated. For the edged hole MIMO RDRA with a slotted ground plane, isolation is better than-24.7 dB at a higher frequency band and is better than-15.5 dB at a lower frequency band. This isolation improvement is explained by the surface current density distribution. The use of an edged hole RDRA and an aperture-coupled orthogonal feeding allows UWB bandwidth and good efficiency performances on the 5G operating bands. To justify the MIMO performance, the envelope correlation coefficient (ECC) and diversity gain (DG) are applied.