Fabrication of electromagnetic crystals by extrusion freeforming

Electromagnetic crystals have potential applications from microwave to optical frequencies. At present, several methods can be applied to fabricate these structures, for example, stereolithography and wafer etching. In this work, extrusion freeforming, one of the linear solid freeforming methods, was used to fabricate electromagnetic crystals and the forming, drying, debinding and sintering stages are described. This method allows structures to be designed on a computer file and rendered directly as physical objects so that prototypes can be created quickly. A wide range of ceramic powders can be used so that dielectric constant and loss factor can be tailored. Structures with deliberate defects such as missing filaments or circular structures can be made.