Microwave dielectric performances of a novel low permittivity NaCaLa(MoO4)3 ceramic for LTCC applications

A novel low-fired NaCaLa(MoO₄)₃ ceramic was synthesized via a conventional solid-state reaction method. The sintering behavior, phase structure, morphology, and microwave dielectric properties of ceramic were systematically investigated. NaCaLa(MoO₄)₃ compound was confirmed to be a single-phase with a tetragonal scheelite structure of I4₁/a space group. The sintering temperature will affect the cationic ordering of NaCaLa(MoO₄)₃ ceramics, thereby affecting the quality factor. NaCaLa(MoO₄)₃ ceramics exhibited a high relative density above 98% in the all sintering ranges, especially the maximum relative density reached 98.34%. The theoretical dielectric constant and packing fraction were calculated based on the refined parameters. The calculations for the chemical bonds of NaCaLa(MoO₄)₃ ceramics show that NaCaLa–O bond and Mo–O bond have the upper hand in dielectric constant and quality factor, respectively. NaCaLa(MoO₄)₃ ceramic sintered at 825 °C demonstrates foremost microwave dielectric properties with low ε_r = 10.72, high Q  × f = 49,495 GHz, and τ_f =  − 49 ppm/°C. Momentously, NaCaLa(MoO₄)₃ ceramic had a good compatibility with Ag powder, suggesting that it is a potential candidate for LTCC applications.