Novel Temperature‐Stable (1‐ x )Ba ₃ V ₂ P ₃ O ₁₅ ‐ x BaV ₂ O ₆ Composite Ceramics with Ultralow Sintering Temperature and Low Dielectric Loss for Dielectric Resonator Antenna Applications

Abstract The phase composition, crystal structures, dielectric properties, and thermal characteristics of novel (1‐ x )Ba ₃ V ₂ P ₃ O ₁₅ ‐ x BaV ₂ O ₆ (0 ≤ x ≤ 1) composite ceramics are systematically investigated. The composite ceramics are rationally designed by combining novel Ba ₃ V ₂ P ₃ O ₁₅ ceramics with BaV ₂ O ₆ ceramics, enabling the regulation of microwave dielectric properties. Experimental results demonstrate that pure‐phase Ba ₃ V ₂ P ₃ O ₁₅ ceramics sintered at 720 °C for 2 h exhibit outstanding microwave dielectric properties: permittivity ( ε _r ) = 7.5, quality factor ( Q × f ) = 25 920 GHz (at 12.22 GHz), and temperature coefficient of resonant frequency ( τ _f ) = −38 ppm °C ⁻¹ . Notably, 0.2Ba ₃ V ₂ P ₃ O ₁₅ ‐0.8BaV ₂ O ₆ ceramics sintered at 580 °C for 2 h achieve excellent microwave dielectric properties: ε _r = 10.0, Q × f = 21 600 GHz (at 10.92 GHz), and τ _f = +3.5 ppm °C ⁻¹ . Additionally, 0.2Ba ₃ V ₂ P ₃ O ₁₅ ‐0.8BaV ₂ O ₆ ceramics exhibit superior terahertz dielectric performance, highlighting significant potential for terahertz applications. Furthermore, 0.2Ba ₃ V ₂ P ₃ O ₁₅ ‐0.8BaV ₂ O ₆ ceramics show favorable compatibility with Al electrodes, demonstrating significant potential for ultralow temperature co‐fired ceramic (ULTCC) application. A cylindrical dielectric resonator antenna (DRA) element is designed using 0.2Ba ₃ V ₂ P ₃ O ₁₅ ‐0.8BaV ₂ O ₆ ceramics, exhibiting a high radiation efficiency of 88.7% and a peak realized gain of 5.56 dBi. Both simulated and measured performances of the DRA are exceptional, indicating its promising applicability in 5.8 GHz Wi‐Fi communication systems.