可調式耦合多頻帶帶通濾波器之研究

本論文針對當今各種無線通訊系統頻帶，提出一系列相關的可調式耦合微帶線帶通濾波器之研究與設計。基於先前的文獻研究，該可調式耦合結構乃由電耦合形式之半波長步階或均勻阻抗共振器及耦合饋入線所組成。首先，一具有高品質響應之帶通濾波器被研究提出。為有別於先前研究及更進一步探討共振器與耦合饋入線最佳的耦合結果，我們採用了阻抗的概念來分析饋入線的耦合特性。額外發現，依據這分析概念，所設計之濾波器，具有一混附波壓抑的特性。其次，我們採用步階式阻抗共振器取代原本的均勻阻抗共振器，來達到一雙頻的響應。經由耦合係數與外部品質因素的相互關係，我們可證明並得到利用改變耦合饋入線線長的方式，所設計之濾波器具有可單獨增強其中一頻帶響應的特性。而後，我們再引入功率的概念，來分析耦合饋入線上的特性。藉此，在不同的基板結構上，設計出兩種不同應用頻帶範圍的三頻濾波器。這兩種濾波器都具有極小的尺寸。最後，根據上述之研究，我們再設計出一四頻濾波器來驗證其應用在多頻帶系統的可行性。此四頻濾波器具有低插入損失、寬廣的通帶選擇範圍、通帶間具有傳輸零點、在通帶邊緣有快速衰減率、易於設計且不需額外的阻抗匹配輸入等優點。

關鍵字

多頻帶帶通濾波器；混附波抑制；步階式阻抗共振器；多層基板

並列摘要

In this thesis, a series of microstrip bandpass filters with a modifiable coupling are proposed for various applications of the modern wireless communication system. Based on previous literatures, the proposed modifiable coupling architecture is composed of one or more sandwiched stepped/uniform impedance half-wavelength resonator pairs which folded in an electric coupling type and input/output feeding lines. A bandpass filter with a high performance is proposed first. To analyze and predict more precisely the optimal coupling position of a uniform impedance resonator pair versus input/output lines, a characteristic impedance concept is introduced and verified by the simulated current distribution. Besides, a feature of spurious suppression based on this concept is discovered and utilized for a wide stopband. Second, a stepped impedance resonator pair, instead of the above uniform one, is introduced for a dual-band frequency response. Through the certification for the relation between the coupling coefficient and external quality factor, the proposed filter has an importance feature that the required passband performance can be enhanced alone by modifying the length of the I/O lines to couple the resonator pair. Then, two kinds of tri-band bandpass filters with different configurations and specifications are proposed. A power analysis is introduced first to explore the modifiable coupling in terms of multi-resonator pairs on a co-planar or multi-layered substrate. Both of them exhibit a compact size and a high performance. Finally, a quad-band bandpass filter based on above technologies and analyses is proposed and realized. The proposed filter has a lot of advantages comparing with other works, such as a low insertion loss, a wide tunable range of either passband, transmission zeros at adjacent passbands, a rapid attenuation at the passband skirt, and easy to design without extra impedance-matching blocks.

並列關鍵字

Multi-band bandpass filter ； Spurious suppress ； Stepped impedance resonator ； Multi-layered substrate

參考文獻

1. 洪政源，2007，應用於微波及毫米波之超寬頻帶通濾波器之設計與製作，博士論文，國立成功大學，微電子工程研究所，台南。

2. Chu, Q. X., Chen, F. C., Tu, Z. H., and Wang, H., 2009, “A Novel Crossed Resonator and Its Applications to Bandpass Filters,” IEEE Trans. Microw. Theory Tech., Vol. 57, No. 7, pp. 1153-1159.

6. Gupta, K. C., Garg, R., Bahl,, I., and Bhartis, P., 1996, “Microstrip Lines and Slotlines,” 2nd ed., Artech House, Boston.

7. Hammerstard, E. O., 1975, “Equations for Microstrip Circuit Design,” Proceeding of the European Microwave Conference, Hamburg, Germany, pp. 286-272.

8. Kobayashi, M., 1988, “A Dispersion Formula Satisfying Recent Requirements in Microstrip CAD,” IEEE Trans. Microw. Theory Tech., Vol. 36, No. 8, pp. 1246-1250.

國際替代計量

可調式耦合多頻帶帶通濾波器之研究

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