Microwave dielectric properties of low loss microwave dielectric ceramics: A0.5Ti0.5NbO4 (A = Zn, Co)

The microwave dielectric properties of low-loss A(0.5)Ti(0.5)NbO(4) (A = Zn, Co) ceramics prepared by the solid-state route had been investigated. The influence of various sintering conditions on microwave dielectric properties and the structure for A(0.5)Ti(0.5)NbO(4) (A = Zn, Co) ceramics were discussed systematically. The Zn0.5Ti0.5Nba4 ceramic (hereafter referred to as ZTN) showed the excellent dielectric properties, with epsilon(r) = 37.4, Q x f = 194,000 (GHz), and tau(f) = -58 ppm/degrees C and Co0.5Ti0.5NbO4 ceramic (hereafter referred to as CTN) had epsilon(r) = 64, Q x f = 65,300 (GHz), and tau(f) = 223.2 ppm/degrees C as sintered individually at 1100 and 1120 degrees C for 6 h. The dielectric constant was dependent on the ionic polarizability. The Q x f and tau(f) are related to the packing fraction and oxygen bond valence of the compounds. Considering the extremely low dielectric loss, A(0.5)Ti(0.5)NbO(4) (A = Zn and Co) ceramics could be good candidates for microwave or millimeter wave device application. (C) 2014 Elsevier Ltd. All rights reserved.