四通道可切換式帶通濾波器之研究;Research on Four-Channel Switchable Bandpass Filter Bank

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Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/81487

Title:	四通道可切換式帶通濾波器之研究;Research on Four-Channel Switchable Bandpass Filter Bank
Authors:	李嘉倫;Li, Chia-Lun
Contributors:	電機工程學系
Keywords:	單刀四擲;柴比雪夫;帶通濾波器;可切換;SP4T;Chebyshev;Bandpass filter;Switchable
Date:	2019-08-13
Issue Date:	2019-09-03 15:56:58 (UTC+8)
Publisher:	國立中央大學
Abstract:	本論文使用SP4T的開關元件，去切換4條不同的通帶路徑，而此四個通帶中心頻率個別為1.25 GHz、1.75 GHz、2.25 GHz、2.75 GHz，都是500 MHz的頻寬，意味著在最低中心頻率的通帶比例頻寬最大。所以本論文比較各種不同的電路，去選擇較適合的電路設計，配合不同中心頻率和比例頻寬的通帶，並且使用金屬屏蔽盒，屏蔽來自外界的雜訊，提高止帶的響應特性，搭配前後各一個SP4T 開關元件，最後設計出四通道可切換式帶通濾波器。利用比較不同論文和文獻上的電路設計，去使用選擇度最好，並且面積較小的設計。比較下來，最低頻且頻寬最大的通帶，則使用三模態共振器去完成，又因為使用較厚的電路板，在共振器之間擁有較大的耦合量，共振器之間可以使用較大的間隙(gap)，提高蝕刻製程的成功率。所以其他三個較低頻寬的通帶可以使用傳統的hairpin帶通濾波器，擁有不錯的選擇度外，電路設計可以使用chebyshev原型參數，套用公式計算出的Q值和M值去匹配電路，擁有完整的設計流程，去完成通帶主體的電路設計。但是中心頻率為2.25 GHz的通帶，因為止帶內有二次諧波產生的旁生通帶，不符合所要求止帶內S21-20 dB的壓制，所以使用步階式阻抗共振器(Stepped Impedance Resonator)，把二次諧波推往更高頻的頻率，讓止帶符合規格要求。而在SP4T的焊接上，針對於QFN (Quad Flat No-Lead )packages 腳位和QSOP-16 (Quarter Size Outline Package) 腳位，則各提出一個不需要過高成本，但是卻可以提高焊接成功率的實務方法，最後完成整個電路設計，整體電路尺寸大小為13 cm × 8.5 cm，各個通帶S21最低點為-5.5 dB、-8.58 dB、-7.84 dB、-7.91 dB，在止帶部分則都低於-20 dB，並且通帶具有可切換的特性。 ;This thesis uses SP4T to switch the four different passband paths. The center frequencies of four passband are 1.25 GHz, 1.75 GHz, 2.25 GHz, and 2.75 GHz. Both of them are 500 MHz bandwidth, and the other hand the lower center frequency, the higher passband bandwidth be. By comparing different circuits, chooses the better circuit design to match the passbands of different center frequencies and bandwidths. With the metal housing to shield the noise from the outside can improve the response of the stopband. And the circuit used two SP4T to complete the design of the four-channel switchable bandpass filter. By comparing the different circuit design, use the design with the best selectivity and smaller area. The three-mode resonator is used to design the band 1. And the others use the hairpin bandpass filter, because the thicker PCB has stronger coupling in the same gap to improve the success rate of the etching process. And even can use the Chebyshev prototype parameters to design the bands systematically. However, the passband of the 2.25 GHz center frequency used stepped impedance resonator (Stepped Impedance Resonator) to make the first harmonic frequency higher. And there are two different welding process for the QFN and QSOP package to improve the success rate of welding and even low cost. The circuit size finally is 13 cm × 8.5 cm. The lowest insertion loss of each passband is 5.5 dB, 8.58 dB, 7.84 dB and 7.91 dB. The S21 of the stop band is all below -20 dB, and each passband is switchable.
Appears in Collections:	[Graduate Institute of Electrical Engineering] Electronic Thesis & Dissertation

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