Temperature Stability Enhancement of Low‐Temperature‐Sintered BaCo ₂ Si ₂ O ₇ Ceramic and Its Antenna Application

In this study, BaCo 2 Si 2 O 7 ceramics with a novel melilite‐type structure (space group C2/c) were synthesized via a solid‐state reaction method. Ba 3 V 2 O 8 with positive TCF value was introduced into (1‐ x )BaCo 2 Si 2 O 7 ‐ x Ba 3 V 2 O 8 composites ( x = 0.1–0.7) to tune the large negative TCF of BaCo 2 Si 2 O 7 ceramics. Furthermore, different amounts of Co 2 O 3 ( y wt%, where y = 1–5) were introduced into the composite ceramics to reduce the sintering temperature. Notably, 0.4BaCo 2 Si 2 O 7 ‐0.6Ba 3 V 2 O 8 ceramics with y = 3 sintered at 925°C exhibit an ε r of 11.04, a Q×f of 16 100 GHz, and a TCF of +0.2 ppm/°C. A 5G millimeter‐wave dielectric resonator antenna (DRA) based on 0.4BaCo 2 Si 2 O 7 ‐0.6Ba 3 V 2 O 8 ‐3 wt% Co 2 O 3 ceramics exhibits a high radiation efficiency of 95.1% and a peak realized gain of 6.12 dBi, indicating the promising applicability of BaCo 2 Si 2 O 7 ‐based ceramics.