Ceramic synthetic substrates using solid freeform fabrication

Three-dimensional (3-D) printing techniques were used to create lost molds for advanced inhomogeneous materials made of ceramics. The utility of this process is the ability to manipulate low-loss materials, such as alumina illustrated here, into precise, fine features as periodic macroscopic inclusions in a larger host material or air. Three periodic structures were formed using solid freeform (SFF) fabrication techniques; a two-dimensional (2-D) alldielectric electromagnetic bandgap (EBG) substrate, a 2-D metallo-dielectric substrate filter, and a 3-D woodpile EBG structure. The design of these structures is discussed and the fabricational steps are presented in detail. This process has been utilized to develop a simple two-pole filter embedded in a substrate at 10 GHz, a single resonator at 30 GHz, and a 3-D bandgap structure from 88 to 115 GHz. The wide range of features and structures that can be accurately fabricated are highlighted.