Improved microwave dielectric properties of CaMgSi2O6 ceramics through CuO doping

Abstract High-performance dielectric materials for microwave communication requires low dielectric constants ( e r Qf ) and near-zero temperature coefficient of resonance frequency ( τ f ). However, CaMgSi 2 O 6 ceramics typically exhibit low Qf and largely negative τ f , despite its low e r . In this study, nominal composition CaMg 1- x Cu x Si 2 O 6 (0 ≤  x  ≤ 0.16) ceramics were synthesized via a solid-state reaction. Enhanced microwave dielectric properties were achieved in the x  = 0.04 ceramic sintered at 1250 °C with e r  = 7.41, Qf  = 160 100 GHz (two times better than the previously reported values), and τ f  = −42 ppm/°C. Benefited from the optimal CuO doping, this enhancement in microwave dielectric property was realized by the contribution of order structure and the densification. Excess CuO doping, which can lead to a phase transition (from C 2/ c to P 2 1 / c ), could degenerate the microwave dielectric properties of the CaMgSi 2 O 6 ceramics. Considering the excellent microwave dielectric properties, the CuO-doped CaMgSi 2 O 6 ceramic is a promising candidate material for microwave communication applications.