High-Q microwave dielectric in the (1-x)MgTiO_3-xCa_(0.6)La_(0.8/3)TiO_3 ceramic system with a near-zero temperature coefficient of the resonant frequency

摘要

The microwave dielectric properties and microstructures of the new (1 -x)MgTiO_3-xA:Ca_(0.6)La_(0.8/3)TiO_3 ceramic system, prepared using a mixed oxide route, were investigated. Combination of MgTiO_3 (MT) and Ca_(0.6)La_(0.8/3)TiO_3 (CLT) forms a two-phase system and leads to a near-zero τ_f. With increasing x, the microwave Q×f decreased and ε_r increased. A microwave dielectric material having a ε_r of 25.45, a Q×f of～82,500 GHz (at 8.5 GHz), and a τ_f of～0.5 ppm/℃ can be obtained from the compound 0.85MgTiO_3-0.15Ca_(0.6)La_(0.8/3)TiO_3 sintered at 1275 ℃ for 4 h. It is proposed as a candidate material for ISM band components and GPS antennas.