In this work, a compact four-element super-wideband (SWB) multiple-input-multiple-output (MIMO) antenna with four notched bands is designed. The unit resonating element of the MIMO antenna consists of a semi-elliptical monopole patch with high eccentricity. The elliptical patch of the antenna element is truncated from the top to develop a polarization diversity-based compact MIMO configuration. In the coplanar ground surface, a flipped-slot of matched geometry is introduced, which complements the truncated antenna element. Also, four slit-resonators are introduced in the radiating patch of the antenna element to eliminate Wi-Fi, WLAN, Wi-MAX, and X-band signals (2.4, 3.5, 5.5, and 8.5 GHz, respectively) from the SWB. In the proposed quad-port SWB-MIMO configuration, the truncated elliptical self-complementary antenna (TESCA) elements are arranged in rotational symmetry and mutually orthogonal to each other. The diversity antenna exhibits impedance bandwidth (for |S11| < −10 dB) from 1.15 to 40 GHz (bandwidth ratio ~35:1), inter-element isolation greater than 18 dB, and ECC < 0.005. The proposed four-element diversity antenna may be a good candidate for cognitive radio and ubiquitous applications.