A conversion device for converting between electric power and electromagnetic waves, such as an RF antenna, may be fitted with an intermediary holographic lens to modify a radiation pattern between an electromagnetic radiation (EMR) reflector to reflect EMR and an EMR feed. The holographic lens may modify a performance metric associated with the conversion device. The holographic lens may have a volumetric distribution of dielectric constants. For example, a voxel-based discretization of the distribution of dielectric constants can be used to generate the holographic lens.