Control of Microwave Emission from Photonic Crystals by Lattice Modification(Materials, Metallurgy & Weldability, INTERNATIONAL SYMPOSIUM OF JWRI 30TH ANNIVERSARY)

Three-dimensional photonic crystals with periodic variations of the dielectric constant were fabricated by using a rapid prototyping method called stereolithography. Millimeter-order epoxy lattices with a diamond structure were designed to reflect electromagnetic waves by forming an photonic bandgap in the GHz range. Titania based ceramic particles were dispersed into the lattice to control the dielectric constant. The diamond lattice structures formed the perfect bandgap reflecting electromagnetic waves for all directions. Diamond structures with stretched lattice spacing were successfully fabricated as well, resulting in the directional transmission of microwaves. A microwave antenna head composed of the normal and stretched diamond structure was fabricated and achieved unidirectional transmission.