Novel Temperature-Stable (1-x)Ba₃V₂P₃O₁₅-xBaV₂O₆ Composite Ceramics with Ultralow Sintering Temperature and Low Dielectric Loss for Dielectric Resonator Antenna Applications

The phase composition, crystal structures, dielectric properties, and thermal characteristics of novel (1-x)Ba₃V₂P₃O₁₅-xBaV₂O₆ (0 ≤ x ≤ 1) composite ceramics are systematically investigated. The composite ceramics are rationally designed by combining novel Ba₃V₂P₃O₁₅ ceramics with BaV₂O₆ ceramics, enabling the regulation of microwave dielectric properties. Experimental results demonstrate that pure-phase Ba₃V₂P₃O₁₅ 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, 0.2Ba₃V₂P₃O₁₅-0.8BaV₂O₆ 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, 0.2Ba₃V₂P₃O₁₅-0.8BaV₂O₆ ceramics exhibit superior terahertz dielectric performance, highlighting significant potential for terahertz applications. Furthermore, 0.2Ba₃V₂P₃O₁₅-0.8BaV₂O₆ 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 0.2Ba₃V₂P₃O₁₅-0.8BaV₂O₆ 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.