Temperature-Stable (1– x )Ba ₁₂ Zn _0.5 Zr _0.5 Nb ₉ O ₃₆ - x BaWO ₄ Composite Ceramics for Low-Temperature Co-Fired Ceramics and Dielectric Resonator Antenna Applications

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 Ba 12 Zn 0.5 Zr 0.5 Nb 9 O 36 ( R 3̅ m ) 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 BaWO 4 ( I 4 1 / a ) for precise τ f tuning and BaCu(B 4 O 8 ) as a sintering aid to enable low-temperature sintering. XRD Rietveld refinement confirms the composites consist exclusively of impurity-free Ba 12 Zn 0.5 Zr 0.5 Nb 9 O 36 and BaWO 4 phases, and Raman spectroscopy validates the characteristic vibrational modes of NbO 6 octahedra and [WO 4 ] 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.