A/B site modified CaTiO3 dielectric ceramics for microwave application

(Li1/2Nd1/2)(2+) substitution into the A site and (Mg1/3Ta2/3)(4+) substitution into the B site of CaTiO3 ceramic were investigated, respectively. The modified CaTiO3 dielectric ceramics prepared by conventional solid-state method exhibit single perovskite structure and improved dielectric properties. Optimal microwave dielectric properties Of epsilon(r) = 112.6, Q x f = 4480 GHz, tau(f) = 8.2 ppm/degrees C in [Ca-0.4(Li1/2Nd1/2)(0.6)] TiO3 and epsilon(r) = 60.2, Q x f = 36900 GHz, tau(f) = -10.1 ppm/degrees C in Ca[Ti-0.4(Mg-1/3 Ta-2/3)(0.6)] O-3 are obtained, which indicates their potential for microwave application. The effects of change of crystal structure on dielectric properties are also discussed.