A printed slot antenna with 10-dB impedance bandwidth from 22.44 GHz to > 67 GHz is presented. The proposed antenna is basically an elliptical slot antenna fed by a microstrip line on the backside of the substrate. To increase the bandwidth, particularly, a parasitic patch loaded by a cross-shaped slot was non-concentrically placed into the elliptical slot and an open-circuited stub was properly added to the feed line. Experimental results show that the fabricated antenna achieves a ratio bandwidth of > 2.99:1 for VSWR 2 and at lower frequencies of the bandwidth it exhibits dipole-like radiation patterns with the peak gain of 8.4 dBi. The proposed antenna is suited to future 5G wireless communications at 28 GHz, 38 GHz, and 60 GHz.