Design and fabrication of gradient index artificial electromagnetic medium based on 3D printing

A novel method will be proposed to realize the integrated design and fabrication of the micro- and macro- structures for the artificial electromagnetic (EM) medium driven by the physical properties of the devices. The mapping relations between feature parameters of the unit cell and the effective permittivity as well as index of the artificial medium have been established with the photonic crystal structures in metamaterial regime. Using these mapping relations, artificial EM medium with gradient index has been designed controllably. Based on the theoretical calculation, the EM wave carpet cloak and black hole are designed with the gradient index artificial medium. These complicated 3D EM devices have been fabricated by using 3D printing process with the photo-curable resin as the raw material. Experimental results show the broadband properties in the Ku frequency range (12-18 GHz) and the controllable transmission for the EM wave in the free space. The possibility to fabricate the EM devices using artificial medium has been demonstrated by the present research, and these will be the foundation for the further industrial applications of 3D printing in EM field.