A new free-space measurement approach is presented to characterize radio frequency (RF) materials and metamaterials over a wide frequency range. In contrast to the traditional spot-focused horn pair system, the proposed technique generates a Gaussian beam with a tight spot, focused on a sample under test via a synthesis using individually measured responses. Therefore, difficulties in fabricating lenses for the conventional spot-focused horn pair are avoided altogether. In this paper, we validate the proposed technique by extracting the permittivity of a known dielectric slab, and subsequently proceed to characterize the transmission properties of metamaterial assembly. The proposed technique can be adapted for measurements in EM facilities using spherical or planar scanning capability.