Two configurations of a modified feather-shaped antenna element are proposed for super wideband (SWB) multiple-input multiple-output (MIMO) applications. The antenna element geometry comprises of a circular slot-loaded feather-shaped radiator and rectangular notch-loaded quarter elliptical coplanar waveguide ground plane. An operating bandwidth of 4.4–51.5 GHz with inter-port isolation, S21 ≥ 15 dB for spatial diversity configuration, and 3.8–51.5 GHz with S21 ≥ 15 dB in pattern diversity configuration are achieved. The footprints of the antenna configurations are 17 × 33 and 31 × 31 mm2. Both configurations exhibited an envelope correlation coefficient of <−20 dB. The proposed MIMO configurations are fabricated and experimentally validated. The designed antenna configurations are SWB and compact.
