The fabrication of composite materials having digitally designed dielectric and magnetic properties varying on a voxel-by-voxel basis offers exciting prospects for additive manufacturing of gradient index lenses for radio frequency (RF) signals. Such lenses will, in the future, be custom printed to form application-specific beam patterns in RF communications systems such as cellular telephone, Wi-Fi, radar, and internet of things (IoT). Here we present materials and methods for the digitally controlled additive manufacturing of magneto-dielectric composites with dielectric permittivity and magnetic permeability programmable on a voxel-by-voxel basis.