Synthesis and microwave dielectric properties of B2O3-doped Mg2GeO4 ceramics

Orthorhombic Mg 2 GeO 4 ceramics were synthesized by solid-state reaction method. When stoichiometric compositions were employed, the phase transition produced under low temperature and pure orthorhombic Mg 2 GeO 4 phase appeared at 1000   °C. B 2 O 3 was employed as sintering aid to lower the sintering temperature of Mg 2 GeO 4 ceramics and improve their relative densities. The B 2 O 3 -doped Mg 2 GeO 4 ceramics have a low sintering temperature of 1250   °C and a small negative τ f value. Microwave dielectric properties of B 2 O 3 -doped Mg 2 GeO 4 ceramics were: ε r   =   6.76, Q   ×   f   =   95,000   GHz and τ f   =   −28.7   ppm/°C. They could be considered as promising candidate materials for microwave/millimeter-wave devices.