High‐Q Microwave Dielectric Materials Based on the Spinel Mg₂TiO₄

Abstract

Composite ceramics based on the spinel Mg2TiO4 were prepared by a conventional mixed‐oxide route. To achieve the temperature stabilization of the dielectric constant, each of the composites was added with 7 mol% CaTiO3. The effect of the substitution of isovalent Co for Mg on the microstructure and the microwave dielectric properties of the composite ceramics was also investigated. A maximum Q×f value of around 150–160 THz was obtained for the undoped Mg2TiO4, whereas a reduced Q×f value was observed for an increase in the Co concentration in the system (1−x)Mg2TiO4−xCo2TiO4. Upon doping with 7 mol% CaTiO3, the Q×f value passed through a maximum with increasing Co concentration. Adding ZnO–B2O3 to the composite system based on Co‐doped Mg2TiO4 resulted in a reduction of the sintering temperature by 150°–200°C without any significant degradation in the Q×f value.

Effect of annealing and atmosphere on the structure and optical properties of Mg2TiO4thin films obtained by the radio frequency magnetron sputtering method

“…Moreover, thin film technology has become a major requirement for integration since integrated circuits have been applied in microwave communication systems. Among other spinels, MTO is a most promising dielectric candidates, having the inverse type spinel belonging to cubic structure with space group (Fd-3 m) N o 227, exhibits an average dielectric constant (" r ) � 14, a high-quality factor (Qƒ 0 ) � 150,000 GHz and a negative temperature coefficient of resonant frequency (� f ) � �50 ppm/ � C [5][6][7][8].…”

Improving the breakdown strength of (Mg0.9Zn0.1)2(Ti1−xMnx)O4 ceramics with low dielectric loss

“…In 2006, Belous et al [3] reported that Mg 2 TiO 4 with a relative permittivity of about 14 exhibits a dielectric loss of less than 10 À 4 . Li [4] recently discovered that the partial substitution of Mg 2 þ by Zn 2 þ in (Mg 1 À x Zn x ) 2 TiO 4 ceramics can inhibit grain growth and improve breakdown strength.…”

A novel low-loss spinel microwave dielectric ceramic CoZnTiO4

“…Recently, M 2 TiO 4 (M = Zn, Mg and Co) spinel-based ceramics are extensively studied as dielectric materials because of its low permittivity and high quality factor [10][11][12]. The introduction of M 2 TiO 4 oxides is of great interest for the generation of new dielectrics.…”