A ultrawideband magnetoelectric dipole (MED) antenna fed by a ridged waveguide is presented in this letter. Different from the widely used Γ-shaped probe feeding structure, a novel ridged waveguide aperture-coupled feeding technology is employed to excite the MED antenna and an ultrawideband MED antenna with an impedance matching of 104% from 1.92 to 6.08 GHz and directional pattern is realized. To verify this design, an antenna prototype is fabricated using the metallic three-dimensional printing technology. The measured impedance bandwidth of VSWR < 2 is 104% from 1.99 to 6.14 GHz. The directional patterns with a stable gain varying from 5.5 to 7.5 dBi are achieved. Besides, high radiation efficiency of above 89% is obtained owing to its all-metallic structure, which avoids the dielectric loss.