| Summary: | 碩士 === 國立聯合大學 === 電機工程學系碩士班 === 100 === This paper is divided into two main parts. In the first part, the effects of B2O3 addition on the sintering behavior and the microwave dielectric properties of CaLa4Ti4O15 ceramics have been discussed. The experiment results show that the CaLa4Ti4O15 ceramics with B2O3 additions can effectively reduce the sintering temperature. At 1220°C, CaLa4Ti4O15 ceramics with 0.5 wt.% of B2O3 additions possesses a dielectric constant of 46, a Q×f value of 23,000GHz, and a temperature coefficient of resonant frequency of -19.72ppm/°C.
Besides, the effects of the microwave dielectric properties of Zr4+ substituted for Ti4+ to from CaLa4(Ti(1-x)Zrx)4O15(x=0.01~0.1) ceramics have been discussed. The experiment results show that the dielectric properties can be inprove with Zr4+ substitution for Ti4+. When x=0.05, the specimen exhibited excellent properties of εr=45.75, Q×f=48,000GHz, τf=-12.32ppm/°C with sintered at 1550°C for 4h.
Finally, the microwave dielectric properties of (1-x)Nd(Co1/2Ti1/2)O3-x(Ca0.8Sr0.2)TiO3 ceramics have been discussed. For this results, a dielectric constant of 44.5, a value of 18,000GHz, and a temperature coefficient of resonant frequency of -2.4ppm/°C for 0.5Nd(Co1/2Ti1/2)O3-0.5(Ca0.8Sr0.2)TiO3 ceramics at 1340°C for 4h is proposed in this experiment.
In the second part, the helix antenna has been designed and fabricated by using 0.5Nd(Co1/2Ti1/2)O3-0.5(Ca0.8Sr0.2)TiO3 ceramic have been discussed.
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