Multi-material additive manufacturing of microwave devices

In recent years, additive manufacturing has evolved to become a key method of prototyping devices across many industrial sectors including electromagnetic systems such as antennas. The range of materials that can now be deposited by 3D printers has expanded the suite of devices that can be rapidly manufactured. In this paper we will present two electromagnetic lenses that demonstrate the advantages of multi-material 3D printing, where a number of different dielectric materials are used to design functional devices with interesting properties. The first example is a frequency dependent dual focusing lens design through topology optimization, using two different dielectric filaments. The second is a compressed Luneburg lens that theoretically requires a continuous permittivity gradient from 7.8 in its centre down to 1 on the surface, and is realised by printing with a total of five different dielectrics.