Sr₂TiO₄ ceramics were synthesized via the conventional solid-state reaction process, and the effects of post-annealing treatment in air on the microwave dielectric properties and defect behavior of title compound were investigated systematically. The Q × f values could be effectively improved from 107,000 GHz to 120,300 GHz for the specimens treated at 1450 °C for 16 h. The thermally stimulated depolarization currents (TSDC) revealed two kinds of defect dipoles [\( \left({\mathrm{Ti}}_{\mathrm{Ti}}^{\hbox{'}}-{V}_{\mathrm{O}}^{\bullet \bullet}\right) \) and \( \left({V}_{\mathrm{Sr}}^{"}-{V}_{\mathrm{O}}^{\bullet \bullet}\right) \)] and oxygen vacancies \( \left({V}_{\mathrm{O}}^{\bullet \bullet}\right) \) were considered the main defects in Sr₂TiO₄. Under a post-annealing treatment in air, the concentrations of such defects in the ceramics decreased. Meanwhile, the impedance spectrum revealed the activation energy of the grain boundaries increased. These evidences could account for the improvement of Q × f values. Accompanied with a high ε_r of 40.4 and a large τ_f of 126 ppm/°C, the enhanced high-Q Sr₂TiO₄ ceramics can be good candidates for applications in wireless passive temperature sensing.

通过传统的固相反应工艺合成了Sr ₂ TiO ₄陶瓷，并系统研究了空气中的后退火处理对标题化合物的微波介电性能和缺陷行为的影响。对于在1450°C下处理16小时的样品，Q  ×  f值可以有效地从107,000 GHz提高到120,300 GHz。热激发的去极化电流（TSDC）揭示了两种缺陷偶极子[ \（\ left（{\ mathrm {Ti}} _ {\ mathrm {Ti}} ^ {\ hbox {'}}-{V} _ {\ mathrm {O}} ^ {\ bullet \ bullet} \ right）\）和\（\ left（{V} _ {\ mathrm {Sr}} ^ {“}-{V} _ {\ mathrm {O}} ^ {\ bullet \ bullet} \ right）\） ]和氧气空位\（\ left（{V} _ {\ mathrm {O}} ^ {\ bullet \ bullet} \ right）\）被认为是Sr ₂ TiO _4中的主要缺陷。在空气中进行后退火处理后，这些缺陷在陶瓷中的浓度降低了。同时，阻抗谱表明晶界的活化能增加。这些证据可以解释Q  ×  f值的提高。伴随有高ε _{- [R} 40.4和大τ _˚F 126 PPM /℃，则增强的高Q的Sr _2层的TiO ₄的陶瓷可以是用于在无线无源温度感测应用的良好候选者。