Microwave dielectric properties of low loss microwave dielectric ceramics:A_(0.5)Ti_(0.5)NbO_4 (A= Zn, Co)

摘要

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 Zn_(0.5)Ti_(0.5)NbO_4 ceramic (hereafter referred to as ZTN) showed the excellent dielectric properties, with ε_r = 37.4, Q × f= 194,000 (GHz), and τ_f= -58 ppm/°C and Co_(0.5)Ti_(0.5)NbO_4 ceramic (hereafter referred to as CTN) had ε_r = 64, Q x/= 65,300 (GHz), and τ_f= 223.2ppm/°C as sintered individually at 1100 and 1120 °C for 6 h. The dielectric constant was dependent on the ionic polarizability. The Q xf and tf are related to the packing fraction and oxygen bond valence of the compounds. Considering the extremely low dielectric loss, (A = Zn and Co) ceramics could be good candidates for microwave or millimeter wave device application.