(183ae) Effects of [Zn0.5Si0.5]3+ Substitution on Microwave Dielectric Properties of ZnAl2-X(Zn0.5Si0.5)xO4 Ceramic

Microwave dielectric properties of low-permittivity ZnAl_2-x(Zn_0.5Si_0.5)_xO₄ (ZAZS) (x = 0.1 – 0.9) ceramics synthesized through solid-state reaction route were investigated. The limitation of the [Zn_0.5Si_0.5]³⁺ ion to substitute the Al³⁺ ion is at x = 0.8. The densification temperature of the ZAZS ceramics showed that partial substitution of [Zn_0.5Si_0.5]³⁺ for Al³⁺ could effectively lowered the sintering temperature of the ZnAl₂O₄. The relative permittivity (ε_r) were greatly affected by the [Zn_0.5Si_0.5]³⁺ partial substitution. The B-site bond valence decreased with increased x value, leading to increased temperature coefficient of resonant frequency (τ_f) in the negative direction. The optimum microwave dielectric properties of ZAZS samples were obtained at x = 0.8 with ε_r = 6.98, Q×f = 20,200 GHz and τ_f = -62 ppm/°C.