本論文將討論介電陶瓷材料系統(1-x)Mg4Nb2O9-xATiO3 (A=Sr、Ca)，藉由正負共振頻率溫度係數的互補，使其達到平衡。Mg4Nb2O9的微波特性為εr~12.9， Q × f ~210000GHz以及τ約-70.4 ppm/℃；SrTiO3為εr~205、Q × f ~4200GHz以及τ約+1700 ppm/℃、CaTiO3為εr~170、Q×f~3600GHz以及τ約+800 ppm/℃，調整x值使其頻率溫度飄移係數趨近於零。在0.6Mg4Nb2O9-0.4SrTiO3材料裡，可在1300oC時燒結且具有最佳介電特性；介電常數εr為21.2，品質因素Q×f~112000GHz(9.7GHz)，共振頻率溫度係數τ為+1.6ppm/oC。在0.5Mg4Nb2O9-0.5CaTiO3材料裡，可在1275oC時燒結且具有最佳介電特性；介電常數εr為24.8，品質因素Q×f為82000GHz(9GHz)，共振頻率溫度係數τ為-0.3ppm/oC。由於添加0.5wt％B2O3於0.6Mg4Nb2O9-0.4SrTiO3材料裡，即可在1200oC時燒結且具有最佳介電特性；介電常數εr為20.53，品質因素Q×f為96000GHz(9.9GHz)，共振頻率溫度係數τ為+2.3ppm/oC。
最後，本論文以FR4、氧化鋁、自製基板0.6Mg4Nb2O9-0.4SrTiO3+0.5wt％B2O3，設計一中心頻率定為2GHz的帶通濾波器，再利用電腦模擬與實做量測結果比較。

The microstructures and microwave dielectric properties of the (1-x)Mg4Nb2O9-xATiO3 (A=Sr、Ca) ceramic system were investigated in this paper. To achieve a temperature-stable material, we studied a method of combing a positive-temperature-coefficient material with a negative one. Mg4Nb2O9 has the following dielectric properties : a dielectric constant of εr~12.9, a Q×f value ~ 210000GHz and a negative τ~ -70.4 ppm/℃. SrTiO3 possesses a dielectric constant of εr~205, a Q × f value ~4200GHz and a positive τ~ +1700ppm/℃.
CaTiO3 possesses a dielectric constant of εr~170, a Q × f value ~3600GHz and a positive τ~ +800ppm/℃.By appropriately adjusting x value in the (1-x)Mg4Nb2O9-xATiO3 (A=Sr、Ca) ceramic system, a zero value can be obtained. With x=0.4 and A=Sr, a dielectric constant
εr~21.2, a Q×f value ~ 112000GHz(at 9.7GHz) and a τ~ +1.6 ppm/℃ were obtained for 0.6Mg4Nb2O9-0.4SrTiO3 ceramics sintered at 1300℃ for 4h. With x=0.5 and A=Ca, a dielectric constant εr~24.8, a Q×f value ~ 82000GHz(at 9GHz) and a τ~ -0.3 ppm/℃ were obtained for 0.5Mg4Nb2O9-0.5CaTiO3 ceramics sintered at 1275℃ for 4h. It is found that 0.6Mg4Nb2O9-0.4SrTiO3 ceramics can be sintered at 1200℃ due to the liquid phase effect of B2O3 additions. At 1200℃, 0.6Mg4Nb2O9-0.4SrTiO3 ceramics with 0.5wt% B2O3 addition possesses a dielectric constant εr~20.53, a Q×f value ~ 96000GHz(at 9.9GHz) and a τ~ +2.3 ppm/℃.
Finally, we design and fabricate a band-pass filters with 2GHz center frequency on FR4、Al2O3、0.6Mg4Nb2O9-0.4SrTiO3+ 0.5wt％B2O3 substrate respectively. And we compared with the result of the simulation and measurement.

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