介電共振器Ba2Ti9O20陶瓷合成的晶相與帶通濾波器的微波特性

作者:鄭秀鳳(國立臺灣師範大學物理學系)

摘要：

本研究已成功設計出一種消散型帶通濾波器，其共振頻率f₀=5.10GHz及帶寬Δf=0.0345GHz，可用來測試Ba₂Ti₉O₂₀材料應用為介電共振器的可行性。長方形共振腔的寬度影響元件之微波截止頻率甚為顯著，然而共振腔長度對元件的影響則較不明顯。另一方面，在共振腔中插入介電物質會降低截止頻率。所通過微波頻帶的中心頻率與介電共振器的共振頻率相同。至於合成Ba₂Ti₉O₂₀介電共振器的材料的方法，以有機金屬物噴霧熱解法較優於共沈法。利用噴霧熱解法可以完全消除BaTi₄O₉及BaTi₅O₁₁中間相的形成。

關鍵詞：微波帶通濾波器、介電共振器、Ba2Ti9O20

《詳全文》

Synthesized Crystal Structure and Microwave Characteristics in Bandpass Filter of Dielectric Resonator Ba₂Ti₉O₂₀ Ceramics

Author: Hsiu-Fung Cheng(Department of Physics, National Taiwan Normal University)

Abstract：

An evanescent bandpass filter with resonance frequency f₀=5.10 GHz and band width Δf =0.0345 GHz has been designed for testing the feasibility of using Ba₂Ti₉O₂₀ materials as dielectric resonators. The width of the rectangular cavity was found to af-fect the cutoff frequency of the device most significantly, while the length of the cavity has least influence. The insertion of the dielectrics, on the other hand, lowers the cutoff frequency. The center frequency of the passing band is the same as the resonance fre-quency of the dielectric resonators. As to the synthesis of the materials for dielectric resonators, i.e., Ba₂Ti₉O₂₀, the sprayed pyrolysis of metallo-organic precursors was found superior to coprecipitation process. The formation of intermediate phases, i.e. BaTi₄O₉, BaTi₅O₁₁, found in coprecipitation process can be completely eliminated by sprayed pyrolysis technique.

Keywords：Microwave bandpass filter, Dielectric resonator, Ba2Ti9O20