| Summary: | 碩士 === 東海大學 === 電機工程學系 === 107 === With the development of wireless communication, people were increasingly dependent on mobile devices. The performance and miniaturization of microwave circuits played an important role. Designing high-stability and miniaturized microwave components was very critical. Therefore, dielectric ceramic materials are currently the better choice for fabricating microwave component substrates. Size reduction of electronic components can be achieved with high dielectric constant, the high quality factor means better ability for storage of the electromagnetic waves energy, and near zero temperature coefficient of resonant frequency means that device could operate stably under wide range of temperature.
The microwave dielectric properties of the [(Mg0.6Zn0.4)]0.95Co0.05]2TiO4 doping with Sn was discussed in this thesis. The experimental results showed that [(Mg0.6Zn0.4)]0.95Co0.05]2(Ti0.95Sn0.05)O4 sintered at 1325 ℃ possessed the best dielectric properties. (εr~15.4, Qൈf~280,000 GHz and τf~-35 ppm/℃) We obtained the better dielectric properties after we doped originalmaterial with Sn. Therefore, we used this main phase material to make further improvement.[(Mg0.6Zn0.4)]0.95Co0.05]2(Ti0.95Sn0.05)O4 prepared by the solid state
synthesis and then mixed with the CaTiO3 and Ca0.6La0.2667TiO3 to improve its microwave dielectric properties. From the experimental results showed that 0.93{[(Mg0.6Zn0.4)]0.95Co0.05]2(Ti0.95Sn0.05)O4}-0.07 CaTiO3 sintered at 1350 ℃ possessed the best dielectric properties (εr~19.93, Q ൈ f~50,000 GHz and τf ~6 ppm/ ℃ ).
0.8{[(Mg0.6Zn0.4)]0.95Co0.05]2(Ti0.95Sn0.05)O4}-0.2Ca0.6La0.2667TiO3 sintered
at 1300 ℃ possessed the best dielectric properties(εr~23.95,Qൈf~57,000 GHz and τf ~5 ppm/℃).
Finally, in order to verify the effect of self-made microwave dielectric materials on the characteristics of microwave components. Step impedance low pass filter was simulated with ADS using following substrates FR4, Al2O3, 0.93{[(Mg0.6Zn0.4)]0.95Co0.05]2(Ti0.95Sn0.05)O4}-0.07CaTiO3, and 0.8 {[(Mg0.6Zn0.4)]0.95Co0.05]2(Ti0.95Sn0.05)O4}-0.2 Ca0.6La0.2667TiO3 self-made substrates. Filter size could be reduced using self-made substrates 0.93{[(Mg0.6Zn0.4)]0.95Co0.05]2(Ti0.95Sn0.05)O4} - 0.07 CaTiO3 and 0.8{[(Mg0.6Zn0.4)]0.95Co0.05]2(Ti0.95Sn0.05)O4}-0.2Ca0.6La0.2667TiO3.
Therefore, overall circuit size could effectively reduce with excellent
microwave component performance.
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