5G and forthcoming 6G communication systems require dielectric ceramics with low relative permittivity (εr) near-zero temperature coefficient of resonant frequency (τf) for the lower part microwave (MW) band at sub-Terahertz. Mg2Al4Si5O18 (MAS) are promising candidates due to their εr (~ 6) high-quality factor (Q×f > 40,000 GHz) but have a large τf. In this study, 5.5 wt% TiO2 (MAS-T5.5) was us...