Effect of lowering the sintering temperature in Mg₄Nb₂O₉ microwave ceramic by doping LMBS glass

Low-temperature co-fired ceramics (LTCC) with excellent microwave dielectric properties have been extensively studied recently due to the increasing demand for miniaturizing microwave devices and reducing the size of wireless communication systems. The Mg₄Nb₂O₉ ceramic, known for its low dielectric loss, is suitable for applications in 5G/6G technology. This research focuses on lowering the sintering temperature of Mg₄Nb₂O₉ ceramic to meet LTCC technology requirements. The results indicate that the Li₂O–MgO–B₂O₃–SO₂ (LMBS) glass demonstrates good wetting behavior and reduces the sintering temperature of Mg₄Nb₂O₉ ceramic from 1350 °C to 950 °C. The phase composition, microstructures, densities, and microwave dielectric properties of Mg₄Nb₂O₉ + x wt% LMBS glass (x = 0, 3, 4, 5, 6) samples are further investigated. Ultimately, the Mg₄Nb₂O₉ + 5 wt% LMBS glass sample exhibits microwave dielectric properties with ɛ_r = 12.16, Q × f = 45,273 GHz, and τ_f = −75.3 ppm/°C.