Dielectric properties of B2O3-doped 0.92(Mg0.95Co0.05)2TiO4-0.08(Ca0.8Sr0.2)TiO3 ceramics for microwave applications

The dielectric properties and microstructures of 0.92(Mg0.95Co0.05)2TiO4-0.08(Ca0.8Sr0.2)TiO3 ceramics with B2O3 additions have been investigated. The sintered 0.92(Mg0.95Co0.05)2TiO4-0.08(Ca0.8Sr0.2)TiO3 ceramics were characterized by using X-ray diffraction spectra, scanning electron microscopy (SEM), backscattering electron image (BEI) and energy dispersive X-ray (EDX). The dielectric properties are strongly dependent on the densifications and the microstructures of the specimens. The decrease of Q × f value at high-level B2O3 addition was owing to the inhomogeneous grain growth and the high-dielectric-loss of the liquid phase. In comparison with that of pure 0.92(Mg0.95Co0.05)2TiO4-0.08(Ca0.8Sr0.2)TiO3 ceramics, specimen with 0.5 wt% B2O3 addition possesses a substantial fine combination of dielectric properties (an ɛr of 18.07, a Q × f of 95,000 GHz at 9.5 GHz and a τf of −4.7 ppm/°C) at a lower sintering temperature of 1200 °C for 4 h. Moreover, a band-pass filter is also designed and simulated on the proposed dielectric to study its performance.