This paper presents an open-ended waveguide structure suited for dielectric lens feeding. The waveguide is buried in the lens body and it is dielectric-filled both to enable to taper-in the cross-section dimensions and to enhance power transfer to the lens. The feed operates in single mode regime and it is designed to produce inside the lens body a linear polarized radiation pattern similar to that of a printed antenna. Two identical tapered dielectric-filled waveguide feeds were designed and fabricated to produce exactly the same radiation pattern at 43 GHz and 62.5 GHz. Tests were performed with different material lenses (ECCOSTOCK, MACOR and PLEXIGLAS). Simulation results were confirmed by measured results.