Effects of packing fraction, lattice vibration, and bond valence on the microwave dielectric properties of low-er garnet-type Ca3Sc2Ge3O12 ceramics

摘要

A low relative permittivity (er) can effectively reduce the signal delay of microwave components. In this study, cubic garnet-type Ca3Sc2Ge3O12 (CSG) ceramics were prepared using a traditional solid-state reaction method. The CSG ceramic exhibited a single phase (space group: Ia-3d) with a cubic garnet-type structure. The ceramic sintered at 1375 degrees C had the best topography and presented the optimal microwave dielectric properties (er = 7.08, Qxf = 34697 GHz, and rf =-20.37 ppm/degrees C). Furthermore, the relationship between the Qxf values and the packing fraction and covalence was discussed, and the effect of lattice vibrations on the internal dielectric loss of CSG was investigated. The internal relationship between the dielectric permittivity and lattice vibration polari-zation was analyzed. The bond valence of the CSG material significantly affected the rf value. The excellent microwave dielectric performance indicated that CSG ceramics are suitable for use in mobile communication base stations, satellite navigation, and radar communications.

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