A Compact Multi-Band MIMO Antenna

This work introduces a low-profile, compact, multi-band antenna. The design consists of 8 rectangular microstrip patch antennas integrated with a slotted Vivaldi. Results indicate that all integrated patches achieve gains above 5 dB even though the radiation patterns of $\hat{y}$ polarized patches are perturbed by the Vivaldi. Despite the low isolation of 6.6 dB and 8 dB between the Vivaldi and the two patches nearest to its feed, isolation greater than 10 dB is achieved between all other antennas. The proposed antenna can be utilized in microcells, repeaters, and may be extended to massive MIMO.