Microwave Dielectric Properties of Gallium‐Doped Hexagonal Barium Titanate Ceramics

High‐permittivity and low‐loss ceramics with composition BaTi 0.92 Ga 0.08 O 2.96 have been prepared in the BaO–Ga 2 O 3 –TiO 2 system using the mixed‐oxide route. This compound forms as the hexagonal polymorph (6 H ) of BaTiO 3 with the space group P 6 3 / mmc . The dielectric properties of dense ceramics have been studied, at microwave frequencies, with the ceramics fired at 1450°C under flowing oxygen gas; the results are a relative permittivity, ɛ r , of ∼74 and a quality factor, Q · f r , of ∼7815 at 5.5 GHz. The quality factor is strongly influenced by the sintering conditions (temperature and atmosphere), whereas the relative permittivity is not influenced significantly by ceramic processing for pellets ≥93% of the theoretical X‐ray density. To our knowledge, this is the first report of microwave dielectric resonance in a perovskite‐type BaTiO 3 ‐based ceramic.