Millimeter Wave Properties of Titania Photonic Crystals with Diamond Structures Fabricated by Using Micro-stereolithography

Three dimensional micro photonic crystals with a diamond structure made of a dense titania were fabricated, and photonic band gap properties in the millimeter waveguides were investigated. Acrylic diamond lattice structures with titania particles dispersion at 40 vol. % were fabricated by using micro-stereolithography. The forming accuracy was 10 mu m. After sintering process, the titania diamond lattice structures were obtained. The relative density reached 96 %. Millimeter wave transmittance properties were measured by using a network analyzer and a W-band millimeter waveguide. In the transmission spectra for the Gamma-X < 100 > direction, a forbidden band was observed from 90 to 110 GHz. The frequency range of the band gap well agreed with calculated results by plane wave expansion (PWE) method. Additionally, simulated results by transmission line modeling (TLM), method indicated that a localized mode can be obtained by introducing a plane defect between twinned diamond lattice structures.