Low-loss microwave dielectric material based on magnesium titanate

Low-loss ilmenite magnesium titanate was synthesized from TiO₂ and MgO powders prepared separately from chemical solutions. Both of these starting materials were very fine and had a high specific area. MgTiO ₃ ceramic had a high quality factor (Q × f) of ∼186 000 GHz when reactive sintering (calcination free) was adopted at 1400°C for 4 h. Moreover, a very high Q × f value of 368 000 GHz (at 10 GHz) was observed when classical solid-state sintering, in which the sintering temperature was as low as 1300°C for 4 h, was applied. The possible mechanism that caused the variation in Q × f values for samples prepared by different sintering processes and initial powders were presented. The proposed low-loss MgTiO ₃ is very promising for microwave or millimeter-wave applications.