Low permittivity ferroelectric composite ceramics for tunable applications

Bulk ferroelectric composite ceramics based on mixtures of BaTiO3/SrTiO(3)powders with Mg-containing additives such as Mg2TiO4, MgO in a wide range of compositions were fabricated and characterized. Phase relations, crystal structures, microstructures and dielectric properties of ferroelectrics were investigated. The best composition with respect to the overall combination of dielectric permittivity, tunability and loss factor was found to have E = 103, tan 0.002 at f = 3.5GHz and tunability 5-6% at a 15kV/cm biasing field. This combination of electrical parameters makes these materials among the most promising candidates for the development of high power tunable components.