Synthesis, characterization and microwave dielectric properties of Zn2GeO4 ceramics

•Zn2GeO4 ceramics were synthesized with solid-state method.•Zn2GeO4 particles were characterized with XRD, FT-IR, Raman spectra and HRTEM.•Microwave dielectric properties of Zn2GeO4 ceramics were: εr = 6.87, Q × f = 102,700 GHz, and τf = −32.4 ppm/°C.•The large relative density, large grain size, uniform microstructures and cation ordering resulted in high Q × f values.•Crystal defect was advantageous to produce small negative τf value.

Zn2GeO4 ceramic materials were synthesized by solid-state method. Zn2GeO4 powders were investigated with X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectrum, Raman spectrum, X-ray photoelectron spectrum (XPS), and high resolution transmission electron microscopy (HRTEM). A dense microstructure of Zn2GeO4 ceramics developed when specimens were sintered at above 1150 °C. The Zn2GeO4 ceramics sintered at 1300 °C exhibited good microwave dielectric properties: a dielectric constant (εr) of 6.87, a quality factor (Q × f) of 102,700 GHz and a temperature coefficient of resonant frequency (τf) of −32.4 ppm/°C. The results showed that Zn2GeO4 ceramics were promising millimeter-wave ceramic candidate materials.