Low-temperature sintering LiF-doped Li4Mg3[Ti0·6(Mg1/3Nb2/3)0.4]2O9 microwave dielectric ceramics for LTCC applications

The LTMN 0.25 + 1 wt% 0.6CuO–0.4B 2 O 3 ceramic with low sintering temperature, small density and excellent performance have wide application prospects in 5G devices. Microwave dielectric ceramics are considered to be one of the key materials of dielectric resonators/filters and have wide application prospects in fifth generation (5G) mobile communication systems. Here we prepared two kinds of low-sintering temperature and high-performance microwave dielectric ceramics with monoclinic rock salt structure by adding a small amount of V 2 O 5 and 0.6CuO–0.4B 2 O 3 sintering aids to Li 2 Ti 0.75 (Mg 1/3 Nb 2/3 ) 0.25 O 3 (LTMN 0.25 ). The sintering temperature of LTMN 0.25 ceramics with 2 wt% V 2 O 5 and 1 wt% 0.6CuO–0.4B 2 O 3 additions could be effectively reduced from 1170 °C to below 910 °C due to the liquid phase effects resulting from the additives. Typically, high performance microwave dielectric properties can be obtained in the LTMN 0.25 + 2 wt% V 2 O 5 ceramic sintered at 910 °C for 2 h, with a ε r ∼ 20.7, a Q × f ∼ 60 460 GHz and a TCF ∼ +4.3 ppm °C −1 . The best dielectric properties of ε r ∼ 19.9, a Q × f ∼ 60 950 GHz and a TCF ∼ −6.1 ppm °C −1 were obtained for the samples with 1 wt% 0.6CuO–0.4B 2 O 3 sintered at 870 °C for 2 h. A prototype dielectric resonator antenna (DRA) was fabricated by LTMN 0.25 + 1 wt% 0.6CuO–0.4B 2 O 3 ceramic. The antenna resonated at 10.02 GHz with a bandwidth ∼175 MHz at −10 dB transmission loss ( S 11 ). Moreover, the chemical compatibility with Ag powder suggests that the LTMN 0.25 + 2 wt% V 2 O 5 and LTMN 0.25 + 1 wt% 0.6CuO–0.4B 2 O 3 ceramics may be suitable candidates for low temperature co-fired ceramic technology applications.