High εr and low loss microwave dielectric ceramics Ba3LiNb3−xTaxTi5O21

High dielectric constant and low loss microwave dielectric ceramics in the system Ba3LiNb3–xTaxTi5O21 (0 ≤ x ≤ 3) have been prepared through solid state ceramic route. The structure and microstructure of the compositions have been studied using powder X-ray diffraction and Scanning electron microscopic studies. The ceramics could be well densified under 1140 °C and exhibited a single hexagonal phase through the entire range of compositions. They show a linear variation of dielectric properties with the value of x. Their dielectric constant (εr) varies from 78 to 55.5, quality factor Q × f increases from 9780 to 18,480 GHz and temperature variation of resonant frequency reduces from +205 to +70 ppm °C−1 as the content of Ta increases. -- Highlights: ► The significant improvement in τf and Q × f are recognized with Ta substitution. ► The ceramics exhibits high εr of 78–55.5 and Q × f of 9780∼18,480 GHz ► The ceramics could be sintered at low temperatures from 1100 to 1160 °C.