在現代的通訊系統的射頻(Radio Frequency)前端電路中，濾波器佔有一個重要的地位。而隨著無線通訊技術的進步與對寬頻的需求越來越高的情況下，現代通訊電路的操作頻率幾乎都落在微波頻段，在微波頻段中，我們通常會利用散佈式元件來實現濾波器，在過去，散佈式元件的低通濾波器或以平行耦合式微帶線帶通濾波器皆廣為被使用來做濾波器的架構，在實用性方面相當的高。但它其中之一的缺點就是在合成濾波器時，其整體的長度過長或的印刷面積過大，這樣大的面積將使得濾波器在微波電路中佔據了過大的面積，如此一來將會與現代通訊系統中所講求的輕、薄、短、小等設計訴求相違背。

本論文為改善散佈式元件的濾波器所造成的面積過大的問題，使用了Defected ground structure 結構和平行耦合開迴路共振子的微帶線結構。底下我們會分別針對兩種結構的原理做說明並且透過全波分析的方式來驗證是否與理論上相符合、並進一步探討如何應用於實際濾波電路上。最後分別利用DGS和平行耦合開迴路共振子結構實作了低通濾波器與帶通濾波器，其實作結果與模擬結果亦都相去不遠。

Using compact structure to improve the defect of traditional transmission line filter which size is too big or transmission line is too long. Two special structures are used to implement the filter that is smaller or superior characteristic.

One of the two structures is called DGS that etched defect in the ground plane. The etched lattice shape for the transmission line consists of narrow and wide etched areas in backside metallic ground, which give rise to increasing the effective capacitance and inductance of a transmission line, respectively. Thus, by using this character, the low-pass filters are designed and implemented easily. Another structure is coupled of microstrip square open-loop resonators. First, the coupling coefficients of the three basic coupling structures versus distance between adjacent resonators and different offset is established by means of three-dimensional field analysis methods. Then, the band-pass filter will be implemented by the combination of three basic coupling structures.

Finally, two low-pass filter which have cutoff frequency 5.4GHz、2.26GHz and a four-pole band-pass filter are designed and fabricated. All theoretical and experimental performance is presented.

致謝……………………………………………………………………………………i
中文摘要………………………………………………………………………………ii
英文摘要……………………………………………………………………………iii
目錄………………………………………………………………………………iv
圖表目錄……………………………………………………………………………v
第一章 序論…………………………………………………………………………1
1.1 概述…………………………………………………………………………1
1.2 論文大綱……………………………………………………………………2
第二章 微波網路理論與微波濾波器的原理和設計流程………………………3
2.1 散射參數法………………………………………………………………3
2.2 微波濾波器的原理和設計流程……………………………………………8
2.2.1 概述……………………………………………………………………8
2.2.2 介入損失法……………………………………………………………9
2.2.3 微波網路濾波器設計方法…………………………………………13
第三章 DGS結構型式的低通濾波器…………………………………………25
3.1 DGS結構的簡介………………………………………………………25
3.1.1 概述………………………………………………………………25
3.1.2 DGS單一細胞的模擬與討論………………………………………26
3.1.3 DGS單一細胞等效模型的參數萃取……………………………28
3.2 週期性的DGS結構……………………………………………………31
3.3 應用DGS結構實現低通濾波器………………………………………34
第四章 交錯耦合型開迴路共振子結構的帶通濾波器…………………………44
4.1 交錯耦合型開迴路共振子的概述………………………………………44
4.2 交錯耦合型濾波器的等效電路與耦合原理……………………………44
4.3 三個基本結構的數值模擬結果與討論…………………………………50
4.4 帶通濾波器的實現………………………………………………………58
第五章 結論………………………………………………………………………62
參考文獻……………………………………………………………………………63

[1] David M. Pozar, “Microwave Engineering”, second edition, John Wiley & Sons, New York, 1998.

[2] Yongxi Qian, Vesna Radisic and Tatsuo Itoh, “Simulation and experiment of photonic bandgap structures for microstrip circuits,” Asia Pacific Microwave Conference, 1997.

[3] V. Radisic and Y. Qian and R. Coccioli and T. Itoh, “Novel 2-D photonic bandgap structure for microstrip lines,” IEEE. Microwave and Guided Wave Letters, vol. 8, NO. 2 pp. 69-71, February 1998.

[4] Miguel A. G. Laso, Txema Lopetegi, Maria J. Erro, David Benito, Maria J. Garde, and Mario Sorolla, “Multiple-frequency-tuned photonic bangap microstrip structures,” IEEE. Microwave and Guided Wave Letters, vol. 10, NO. 6 pp. 220-222, June 2000.

[5] Chul-soo Kim and Jun-Seok Park and Dal Ahn and Jae-Bong Lim, “A novel 1-D periodic defected ground structure for planar circuits,” IEEE. Microwave and Guided Wave Letters, vol. 10, NO. 4 pp. 131-133, April 2000

[6] Dal Ahn and Jun-Seok Park and Chul-soo Kim and Juno Kim and Y. Qian and T. Itoh, “A design of the low-pass filter using the novel microstrip defected ground structure,” IEEE Trans. Microwave Theory and Tech., vol.49 NO. 1, January 2001.

[7] J. S. Hong and M. J. Lancaster, “Coupling of microstrip square open-loop resonators for cross-coupled planar microwave filters,” IEEE Trans. Microwave Theory and Tech. ,MTT-44, No. 12, pp.2099-2109, Dec. 1996.

[8] J. S Hong and M. J. Lancaster, “Theory and experiment of novel microstrip slow-wave open loop resonator filters,” IEEE Trans. Microwave Theory and Tech., vol.45 NO. 12 pp. 2358-2365, Dec. 1997.




[9] J. S Hong and M. J. Lancaster, “Design of highly selective Microstrip bandpass filters with a single pair of attenuation poles at finite frequency,” IEEE Trans. Microwave Theory and Tech., vol.48 NO. 7, July 2000.

[10] M. Sagawa, K. Takahashi, and M. Makimoto, “Miniaturized Hairpin resonator filters and their application to receiver front-end MIC’s,” IEEE Trans. Microwave Theory and Tech., vol.37 NO. 12 pp. 1991-1997, Dec. 1989.

[11] R. Levy, “Filters with single transmission zeros at real or imaginary frequencies,” IEEE Trans. Microwave Theory and Tech., vol.24 No. 4, pp.172-181,April 1976.

[12] J. S. Wong, “Microstrip tapped-line filter design,” IEEE Trans. Microwave Theory and Tech., vol. MTT-27, pp. 40-50, Jan. 1979.