Sintering behavior, crystal structure, and microwave dielectric properties of a novel diopside SrMgGe2O6 ceramic and adjustment of its zf value

A solid-state process was used to synthesize novel microwave dielectric SrMgGe2O6 ceramics. X-ray diffrac-tometry revealed that these ceramics have monoclinic structures that belong to the C2/c space group. A dense SrMgGe2O6 ceramic was obtained at the optimal sintering temperature of 1225 degrees C, the ceramic exhibited excellent microwave dielectric properties, with er = 8.58, Qxf = 56800 GHz, and zf =-59.06 ppm/degrees C. The zf value is affected by the bond valence and bond energy of the Ge-O bond. The addition of CaTiO3 or TiO2 suc-cessfully adjusted the zf value to approximately zero, with the optimal CaTiO3- and TiO2-included composite ceramics exhibiting excellent dielectric properties, with er = 11.74, Qxf = 22056 GHz, zf = +0.18 ppm/degrees C, and epsilon r = 12.32, Qxf = 20930 GHz, zf =-2.27 ppm/degrees C, respectively.