Composite dielectrics (1-x)(Mg_(0.97)Zn_(0.03))_2 (Ti_(0.95)Sn_(0.05))O_4-xCaTiO_3 suitable for microwave applications

摘要

(Mg_(0.97)Zn_(0.03))_2(Ti_(0.95)Sn_(0.05))O_4 ceramics by adding CaTiO_3 have been prepared via the solid-state reaction method. The microstructures of samples are systematically studied in order to establish the effects of sintering temperature and additives on microwave dielectric properties of (Mg_(0.97)Zn_(0.03))_2(Ti_(0.95)Sn_(0.05))O_4 ceramics by X-ray diffraction and scanning electron microscopy. A fine combination of microwave dielectric properties (ε_r = 14.57, Q × f = 183,468 GHz, τ_f = -43.7 ppm/℃) was achieved for (Mg_(0.97)Zn_(0.03))_2(Ti_(0.95)Sn_(0.05))O_4 ceramics sintered at 1,390 ℃ for 4 h. CaTiO_3, as a τ_f compensator, was added to form a temperature-stable ceramic system. For (1- x) (Mg_(0.97)Zn_(0.03))_2(Ti_(0.95)Sn_(0.05))O_4-xCaTiO_3 system, 0.93(Mg_(0.97)Zn_(0.03))_2(Ti_(0.95)Sn_(0.05))O_4-0.07CaTiO_3 ceramic sintered at 1,390 ℃ had optimal dielectric properties (ε_r = 18.32, Q × f = 94,715 GHz, τ_f = -4.1 ppm/℃) which satisfied microwave applications in resonators, filters and antenna substrates.