| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 96 === There are two main subjects in this paper. First, we will discuss the low loss dielectric material, and try to make temperature coefficient of resonant frequency near zero. Second, there will be a discussion of microstrip filter and improvement of circuit size in different substrates.
First, the microwave dielectric properties of (1-x)ZnAl2O4-xTiO2 have been investigated. The experiment results show that (1-x)ZnAl2O4-xTiO2 has the best properties at x=0.5 and sintering temperature 1390℃ for four hours, which could reach the best dielectric properties εr~ 25.2, Q×f ~ 277000(at 9GHz) and τƒ~ +185 ppm/oC. Concerning about the positive value of , we choose adding the Mg0.95Co0.05TiO3(τƒ~-55 ppm/oC) and Mg0.95Zn0.05TiO3(τƒ~-40 ppm/oC) to adjust the value, then we could make temperature coefficient of resonant frequency near zero.
Besides, hairpin planar filter were studied in second section which achieved spurious responses supression by properly choosing the different stepped- impedance ratio. We simulated it by electromagnetic simulation software (HFSS) at the setting of center frequency 2.45GHz and bandwidth 7%. Also, we try to realize that the improvement of Insertion Loss and circuit size at the substitution of FR4, Al2O3 and 0.5ZnAl2O4-0.5TiO2(ZAT) for the microstrip bandpass filter.
|
|---|
