精緻型耦合方形迴路與髮夾梳型高溫超導微波帶通濾波器

Abstract

我們在10*10 平方公分鋁酸鑭基板之雙面成長高溫超導釔鋇銅氧薄膜，並利用微影蝕刻技術，分別製作六階的髮夾梳型微波帶通濾波器以及四階的密集式交錯耦合型方形開迴路共振腔微波帶通濾波器。量測的結果顯示，髮夾梳型微波帶通濾波器，其中心頻率為8.19 GHz，比例帶寬3%，通帶的插入損耗為0.1 dB；密集式交錯耦合型方形開迴路共振腔微波帶通濾波器，其中心頻率為3.01 GHz，比例帶寬3.7%，通帶的插入損耗為0.1 dB。實際元件與電腦模擬的結果相當吻合。 值得強調的是，中心頻率為3.01 GHz之密集式交錯耦合型方形開迴路共振腔帶通濾波器，就我們所知，是目前最小之濾波器元件且插入損耗也是最低。

6-pole hair-pin and 4-pole cross coupled square loop bandpass filters have been successfully obtained by using high-temperature superconducting (HTS) thin films deposited double-sided on LaAlO3 substrates. The 6-pole hair-pin filter displayed an 8.25 GHz passband center frequency, 3.1% fractional bandwidth and 0.1 dB insertion loss. While the 4-pole cross coupled bandpass filter has a 3.01 GHz passband center frequency, 3.7% fractional bandwidth and 0.1 dB insertion loss, respectively. The resulting characteristics of these filters correspond to the simulated results of the designed devices extremely well. In particular, to the best of our knowledge, the 4-pole cross coupled bandpass filter not only is the smallest filter but also has the lowest insertion loss microwave device to date.