© 2021, Electromagnetics Academy. All rights reserved.—In recent years, additive manufacturing has found increasing interest in the fabrication of dielectric antennas. Using additive manufacturing brings significant advantages such as design flexibility, compactness, fast and low-cost manufacturing compared to traditional fabrication methods. Dielectric antennas having dense material allow high power transfer efficiency through the lens. However, a successful 3D printing process with dense dielectric materials is a great challenge. This paper investigates the impact of main process parameters during 3D printing; namely printing speed, process temperature, and layer height on the resulted relative electrical permittivity values of dense dielectric materials. Test samples are printed with a dielectric material having εr = 10, and relative permittivity variations of these samples are measured with a vector network analyzer in X-band (8.2–12.4 GHz). In this way, optimum printing parameters are determined. The influence of dielectric constants of printed materials on the antenna radiation characteristics is inspected for an extended hemispherical lens antenna by a full-wave computer-aided design tool. Results demonstrate that an additively manufactured dense dielectric antenna will act as a traditionally manufactured dielectric antenna if and only if it is manufactured with optimum printing parameters.