Microwave dielectric properties of (Ba1-xMgx)5Nb4O15 ceramics

The effects of magnesium substitution for barium on the microstructure and microwave dielectric properties of Ba5Nb4O15 are investigated using X-ray diffractometry, scanning electron microscopy, Raman spectroscopy, and microwave dielectric properties measurement. The structure of NbO6 octahedra and the ionic polarizability have a significant effect on the relative permittivity (epsilon(r)). Furthermore, a distinct correlation is noted between the secondary phases and microwave dielectric properties. The magnesium substitution at x = 0.6 for (Bal(1-x)Mg(x))(5)Nb4O15 formulation has the 27.6 of epsilon(r), 13,985 GHz of Q x f, and 2.5 ppm/degrees C of tau(f), and it is suitable for microwave resonator application.