Temperature-stable and medium-high K of Ti/W co-doped M-phase LNT microwave ceramics for LTCC dielectric devices

The increasing demand for miniaturized electronic devices requires the development of advanced medium-high K materials. In this work, novel (Ti1/2W1/2)5+-substituted LiNb0.6-x(Ti1/2W1/2)xTi0.5O3 (LNT-xTW, 0 ≤ x ≤ 0.12) ceramics were successfully prepared by the solid-state method. The increase in TW content led to the formation of LNT-0.08 TW ceramic with medium-high K and high Q × f after sintering at 1050 °C. This ceramic also recorded improved characteristics with εr∼53.84, Q × f∼7482 GHz and τf∼43.43 ppm/°C related to ionic polarizability, large grains, high densification, and [Ti2O3]2+/N layers. In addition, Li2O–B2O3–SiO2–CaO–Al2O3 (LBSCA) used as an effective sintering aid, improved densification and promoted sintering by not only decreasing the temperature to 900 °C, but also enhancing the microwave dielectric properties with εr∼49.46, Q × f∼8149 GHz, and τf∼12.04 ppm/°C. The Q × f value was estimated to 1.15 ∼ 2-fold higher than other LNT-based ceramics within stable τf. More encouragingly, the LNT-0.08 TW ceramic also showed good chemical match with Ag, suggesting usefulness for miniaturized LTCC devices.