Effects of Ca/Ti Cosubstitution upon Microwave Dielectric Characteristics of CaSmAlO4 Ceramics

(Ca1+xSm1-x)(Al1-xTix)O-4 (0 <= x <= 0.4) ceramics were synthesized by solid-state reaction method and their microstructures and microwave dielectric properties were investigated. X-ray diffraction analysis and energy-dispersive X-ray analysis indicated that the matrix phase was a solid solution with a composition represented by the chemical formula (Ca1+xSm1-x) (Al1-xTix)O-4 and minor amount of (Ca,Sm)(Al,Ti)O-3 secondary phase was detected. Ca/Ti cosubstitution could significantly improve the microwave dielectric characteristics of CaSmAlO4 ceramics, and the excellent microwave dielectric characteristics were obtained in the modified ceramics as epsilon(r)=19-23, Q x f=49 100-118 700 GHz, and tau(f)=-15-15 ppm/degrees C.