Phase Evolution and Microwave Dielectric Properites in the Systems of (Mg1-xCax)2SiO4 Ceramics

In this paper, the microwave dielectric properties in the systems of nominal chemical composition (Mg(1-x)Ca(x))(2)SiO(4) (0 <= x <= 0.5)ceramics were investigated, together with their phase evolution. With the increase of x value, the major phase in the ceramic systems gradually changes from Mg(2)SiO(4) to MgCaSiO(4), besides with the some secondary phase of MgSiO(3) and Ca(2)MgSi(2)O(7), The relative dielectric constant in the systems of ceramics gradually increased from 6.8 to 8.7. The quality factor of Q value was well improved, and especially, the absolute value of the ceramic resonant frequency of temperature coefficients was optimized to reach zero, from -61 ppm / degrees C to +3 ppm / degrees C. The best optimum chemical composition was equal to 0.4, where the microwave dielectric properties was epsilon(r) = 7.2, Qx f = 24,170 GHz, tau(f) = +5 ppm / degrees C.