Microwave dielectric properties of high dielectric tunable - low permittivity Ba0.5Sr0.5TiO3-Mg2(Ti0.95Sn0.05)O4 composite ceramics

Ba0.5Sr0.5TiO3-Mg2(Ti0.95Sn0.05)O4 composite ceramics have been synthesized by the solid-state reaction. Phase structure, microstructure and microwave dielectric properties have been systematically characterized. The permittivity is tailored to a certain extent with the addition of Mg2(Ti0.95Sn0.05)O4. Both X-ray diffraction (XRD) and back electric image (BEI) analysis show the co-existence of two-phase structures of ABO3 perovskite and A2BO4 spinel structure. A high dielectric tunablity can be obtained and a high Q value can be achieved at microwave frequency. The composition 30 wt.%Ba0.5Sr0.5TiO3-70 wt.%Mg2(Ti0.95Sn0.05)O4 exhibits good dielectric properties with ɛ of 79, Q of 152 (at 2.997 GHz) and T of 15.8% (30 kV/cm & 10 kHz) at room temperature, which make it a promising candidate for tunable microwave device applications in the wireless communication system.