Effects of Mg/Si Ratio on Microwave Dielectric Characteristics of Forsterite Ceramics

Abstract

Nonstoichiometric Mg 2 SiO 4 forsterite dielectric ceramics with various Mg/Si ratios ( R =2.025, 2.05, and 2.2) were prepared and characterized. The appearance of a MgSiO 3 secondary phase could be effectively suppressed by adjusting the nonstoichiometry, and a single‐phase forsterite structure was obtained in the present ceramics with Mg/Si ratios of 2.025 and 2.05. The microwave dielectric characteristics were significantly improved in the nonstoichiometric Mg 2 SiO 4 ceramics on eliminating the MgSiO 3 secondary phase, where an enhanced Q × f value and a suppressed temperature coefficient of resonant frequency λ f were obtained. The best microwave characteristics were achieved in the nonstoichiometric forsterite ceramics with an Mg/Si ratio of 2.05: ɛ r =7.5, Q × f =114 730 GHz, and λ f =−59 ppm/°C.