Temperature-Stable (1-x)Ba₁₂Zn_0.5Zr_0.5Nb₉O₃₆-xBaWO₄ Composite Ceramics for Low-Temperature Co-Fired Ceramics and...

Low-temperature Co-Fired Ceramics necessitate low sintering temperatures to enable cofiring with base metals, while dielectric resonator antennas demand temperature-stable dielectric properties; hexagonal perovskite Ba₁₂Zn_0.5Zr_0.5Nb₉O₃₆ (R3̅m) ceramics exhibit excellent microwave dielectric performance but suffer from a high sintering temperature (1475 °C) and undesirably high temperature coefficient of resonant frequency (τ_f = 26.4 ppm/°C), limiting their practical applications. A synergistic strategy overcomes these critical bottlenecks by integrating BaWO₄ (I4₁/a) for precise τ_f tuning and BaCu(B₄O₈) as a sintering aid to enable low-temperature sintering. XRD Rietveld refinement confirms the composites consist exclusively of impurity-free Ba₁₂Zn_0.5Zr_0.5Nb₉O₃₆ and BaWO₄ phases, and Raman spectroscopy validates the characteristic vibrational modes of NbO₆ octahedra and [WO₄]^2- groups. The optimal composite at x = 0.89 exhibits exceptional all-around microwave dielectric properties (ε_r = 19.0, Q × f = 30100 GHz, τ_f = 3.0 ppm/°C) when sintered at 1000 °C, coupled with excellent chemical compatibility with Cu electrodes during cofiring. The DRA based on this composite delivers a broad 375 MHz bandwidth, 5.13 dBi gain, and 97.17% radiation efficiency at 9.14 GHz, highlighting its great potential for LTCC technology and microwave communication applications.