Microwave dielectric properties of Li_1+x-yM_1-x3yTi_x+4yO₃ (M=Nb⁵⁺,Ta⁵⁺) solid solutions

A series of new low sintering temperature microwave resonator ceramics were investigated in the Li_1+x-yNb_1-x-3yTi_x+4yO₃ solid solution system. Ceramics with high relative permittivities (78-55), Qxf values up to 9000 (6 GHz), and zero temperature coefficients in the microwave region could be obtained via sintering at 1100°C. Similar phases were identified in the Li₂O-Ta₂O₅-TiO₂ system and their stability region at 1100°C was determined. The microwave dielectric properties of the tantalates were similar to those of their Nb counterparts. The addition of ≥ 2 mol% V₂O₅ to the Nb solid solutions was effective in producing a large reduction in the sintering T and dense ceramics could be prepared at T ≤ 900°C. The addition of V did not induce any significant degradation of the microwave properties and their apparent compatibility with Ag powder may indicate potential applications as co-fired circuit components.