Microwave dielectric properties of pure YAG transparent ceramics

The microwave dielectric properties of YAG transparent ceramics were investigated. The samples were prepared by the conventional solid-state reaction technique with the high purity raw materials. And they were sintered at 1600-1800 degrees C for 4-12 h in the vacuum atmosphere <= 1 x 10(-3) Pa. YAG transparent ceramics sintered at 1750 degrees C for 8 h had the pure cubic YAG phase and pore-free microstructure with relative density 99.8%, and they were highly transparent. YAG transparent ceramics had the outstanding microwave dielectric properties: epsilon(r) = 10.8, Q x f=213,400 GHz and tau(f) = -30 ppm/degrees C. The high Q x f value and low er suggested that YAG transparent ceramics would be kind of promising microwave dielectric substrate materials. (C) 2016 Elsevier B.V. All rights reserved.