Temperature-stable Ba0.8Sr0.2CuSi2O6 microwave dielectric ceramics for LTCC application achieved with the addition of LBSCA and LBBS glass

Ba 0.8 Sr 0.2 CuSi 2 O 6 ceramics have a low dielectric constant, which is useful for low-latency 5G communication. To enable the preparation of Ba 0.8 Sr 0.2 CuSi 2 O 6 low-temperature co-fired ceramic (LTCC) materials, LBSCA and LBBS were used in this paper to reduce the sintering temperature of Ba 0.8 Sr 0.2 CuSi 2 O 6 . The effects of LBSCA and LBBS on the phase composition, densification, microscopic morphology, and vibrational characteristics of the ceramics were investigated by X-ray diffraction, scanning electron microscopy, density measurements, and Raman spectroscopy , and the causal factors influencing the microwave dielectric properties with the addition of glass were analyzed. It was found that 0.4 wt% LBSCA glass and 1 wt% LBBS glass reduced the sintering temperature to 925 °C, and these prepared ceramics had excellent microwave dielectric properties. The ceramic prepared with 0.4 wt% LBSCA glass had an ε r value of 7.672, Q × f value of 37193 GHz, and τ f value of −14.93 ppm/°C, while the ceramic prepared with 1 wt% LBBS glass had an ε r value of 7.512, Q × f value of 32136 GHz, and τ f value of −13.92 ppm/°C. The phase composition of the ceramics did not significantly change, indicating that neither glass reacted with the ceramics. The ε r value was affected by both density and Raman shift, the trend in the Q × f values was consistent with the density, and the τ f value decreased with increasing glass content, which was attributed to the liquid phase generated by the glass in the ceramic. In addition, co-firing these glass-doped ceramics with Ag at a low temperature resulted in good chemical compatibility. Combined with the near-zero τ f , these results demonstrate the excellent promise of these two ceramics as alternative materials for LTCC microwave devices and their application in 5G communication.