A dual-band and dual-polarized antenna element for K/Ka-band satellite communication systems is presented. An orthomode transducer (OMT) excites circular polarization in a square substrate integrated waveguide (SIW), that feeds an extended hemispherical dielectric lens. The feed structure is composed of a multilayer printed circuit board (PCB) and tapered superstrates. The design procedure of the components is explained and the antenna performance is presented. The measured scattering and far-field parameters validate the concept.