Microwave dielectric properties and sintering behaviors of (Mg_0.95Ni_0.05)TiO₃-CaTiO₃ ceramic system

The microwave dielectric properties and sintering behaviors of the new ceramic system (1 - x)(Mg_0.95Ni_0.05)TiO₃-xCaTiO₃ (x ≤ 0.1) prepared by conventional solid state route were investigated. The compositions with x = 0.02-0.1 resulted in the mixture of two main phases, (Mg_0.95Ni_0.05)TiO₃ and CaTiO₃, and a second phase (Mg_0.95Ni_0.05)Ti₂O₅, which was favorable at high temperatures. The two-phased system was confirmed by both XRD and EDS analysis. Zero τ_f can be achieved by appropriately adjusting the compositional ratio. Specimen with x = 0.06 possessed an excellent combination of microwave dielectric properties: ε_r ∼ 20.8, Q × f ∼ 79,200 GHz and τ_f ∼ 1.2 ppm/°C. It is proposed as a candidate material for GPS patch antennas and ISM band filters.