Microwave dielectric properties of Li1+x–yM1–x–3yTix+4yO3 (M=Nb5+, Ta5+) solid solutions

A series of new low sintering temperature microwave resonator ceramics were investigated in the Li1+x–yNb1–x–3yTix+4yO3 solid solution system. Ceramics with high relative permittivities (78–55), Q×f 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.