| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 97 === 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 passive components and improvement of circuit size in different substrates.
First, the microwave dielectric properties of Ca0.8Sr0.2TiO3 have been investigated. The experiment results show that Ca0.8Sr0.2TiO3 has the best properties at sintering temperature 1350℃ for four hours, which could reach the best dielectric properties ~ 181, Q×f ~ 8300(at 9GHz) and ~ +991 ppm/oC. Concerning about the positive value of , we choose adding the Mg0.95Ni0.05TiO3( ~ -45 ppm/oC)、Mg0.95Co0.05TiO3( ~ -55 ppm/oC) and Mg0.95Zn0.05TiO3( ~ -40 ppm/oC) to adjust the value, then we could make temperature coefficient of resonant frequency near zero.
Besides, with open stubs parraell-coupled lines bandpass filter were studied in second section which achieved two transmission zeros at passband edges and spurious responses supression by properly choosing the stubs locations and impedances. We simulated it by electromagnetic simulation software (IE3D) at the setting of center frequency 2.4GHz and bandwidth 7%. Also, we try to realize that the improvement of Insertion Loss and circuit size at the substitution of FR4, Al2O3 and 0.95MZT-0.05CST for the microstrip bandpass filter.
Finally,with two open stubs as radiators microstrip patch antenna were proposed. We simulated it by electromagnetic simulation software (HFSS) at the setting of center frequency 1.57GHz for GPS.Then a dual-band dielectric resonator antenna using aperture-coupled were proposed.We used 0.95MZT-0.05CST bulk as a resonator for 5 GHz bands, and dual-band antenna well covered IEEE 802.11n/p communication protocol.
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