Studies on the (1-x)(Mg_(0.7)Zn_(0.3))TiO_3-xCa_(0.61)La_(0.26)TiO_3 Microwave Dielectric Ceramics System

The microstructures and the microwave dielectric properties of the(1-x)(Mg0.7Zn0.3)TiO3-xCa0.61La0.26TiO3(MZT-CLT) ceramic system were investigated.The objective of the present work is to compensate for the negative temperature coefficient of resonant frequency of(Mg0.7Zn0.3)TiO3 by the addition of(Ca0.61La0.26)TiO3.MZT-CLT ce-ramics exhibited mixed phases of(Mg0.7Zn0.3)TiO3 as the main phase associated with minor phases of Ca0.61La0.26TiO3 and(Mg0.7Zn0.3)Ti2O5.The microwave dielectric properties are strongly correlated with the sintering temperature and the composition.Very dense MZT-CLT ceramics were synthesized by sintering at 1275℃.When the samples were sintered at temperatures above 1300℃,the evaporation of Zn resulted the decrease in density and degradation in di-electric properties.With the increasing of x,the relative dielectric constant(er) of the ceramics increases and the prod-uct of quality factor and resonant frequency(Q.f) decreases.The er,Q.f and temperature coefficient of resonant fre-quency(τf) of 0.87(Mg0.7Zn0.3)TiO3-0.13Ca0.61La0.26TiO3 ceramic sintered at 1275℃ are 26,86000 GHz and -6×10-6/℃,respectively.