Microwave Dielectric Properties of Fused Silica Prepared by Different Approaches

摘要

Fused silica was prepared by different approaches, and the microwave dielectric properties were investigated. For the fused silica sintered at 1100℃ by solid-state sintering, the dielectric constant (ε_r) and Qf value increased with increasing the sintering time up to 5 h, while the temperature coefficient of resonant frequency (τ_f decreased. The optimal properties with low ε_r of 3.72, high Qf value of 44,300 GHz, and low τ_f of -14.4 ppm/℃ were achieved when sintered at 1100℃ for 5 h. The microwave dielectric properties could be further improved by other preparing approaches, as listed below: ε_r = 3.90, Qf= 63,500 GHz, τ_f= -5.7 ppm/℃ for spark plasma sintering, and ε_r = 3.83, Qf= 122,100 GHz, τ_f= -8.3 ppm/℃ for melting method. The results showed that fused silica was a good candidate as a microwave substrate material.