High‐ <i>Q</i> and near‐zero <i> τ _f </i> of low‐temperature sintered NaSrYb(Mo ₁₋ <i> _x </i> W <i> _x </i> O ₄ ) ₃ microwave dielectric ceramics and patch antennas

Abstract In response to the growing demand for low‐loss and thermally stable LTCC dielectrics suitable for 5G Sub‐6 GHz applications, a series of W 6+ ‐substituted NaSrYb(Mo 1− x W x O 4 ) 3 (NM 1− x W x , x = 0.02–0.10) ceramics was synthesized through a conventional solid‐state reaction route, and the influence of W 6+ incorporation on the crystal structure, microstructural evolution, and microwave dielectric behavior was comprehensively examined. XRD confirmed that all compositions were stabilized in a single‐phase tetragonal scheelite lattice (space group I 4 1 / a ). SEM and density revealed that moderate W 6+ substitution facilitated homogeneous grain development and enhanced densification. Among the investigated samples, the x = 0.06 composition exhibited superior dielectric performance, characterized by ε r = 10.12, Q×f = 98 018 GHz, and τ f = –8.67 ppm/°C. Raman spectroscopy was utilized to investigate the lattice vibrational modes, while the P–V–L approach was applied to clarify structure–property correlations. FTIR spectra further substantiated ionic displacement polarization as the principal dielectric mechanism. The materials maintained low‐loss characteristics even in the terahertz regime, and a microstrip patch antenna constructed on an NM 0.94 W 0.06 ceramic substrate successfully operated within the 5G Sub‐6 GHz frequency range, thereby validating its strong applicability in next‐generation communication technologies.