具高頻率選擇性與寬截止頻帶之縮小化帶通濾波器

本篇論文針對具有高頻率選擇性的開回路交錯耦合平面式帶通濾波器提出幾個縮小化架構，首先是利用步階阻抗諧振器的特性將其中1個或2個諧振器縮小並崁入到其它諧振器之中來節省電路面積，此架構並不會影響到原本利用電場與磁場交錯耦合產生相位差的耦合機制，和其它已經發表的架構相比有較小的電路面積，並且具有高頻率選擇性，接下來再提出以步階阻抗加彎折微帶線的方式來實現崁入式交錯耦合帶通濾波器，此架構和前面所介紹的架構相比可以有24.5%的面積縮小率，此外針對前面所提的縮小化架構我們也提出具有寬截止帶的低通濾波器架構去改善高頻截止帶的特性，它是利用帶刺微帶線和四分之一波長開路殘段的帶拒濾波器特性，分別設計出具有多個不同中心頻率的截止點來產生寬截止帶的效果，此低通濾波器架構的-10dB頻寬最大可以達到7GHz，搭配前面所提的縮小化帶通濾波器架構可以使濾波器產生寬的截止頻帶，經過模擬與實作量測結果證明此架構可以達到12.98GHz的-20dB截止帶頻寬，並且具有良好的通帶介入損耗與頻率選擇性。

關鍵字

高頻率選擇性；開回路交錯耦合；帶通濾波器；縮小化；步階阻抗；崁入式交錯耦合；寬截止帶；帶刺微帶線；四分之一波長開路殘段

並列摘要

This thesis present some miniaturized open loop cross-coupled planar microwave bandpass filter with high selectivities.First,The bandpass filters were miniaturized by stepped impedance resonators (SIR’s) in which 1 or 2 resonators were embedded in another resonators to reduce circuit size.This structure had no effect on the coupled mechanism that has phase difference caused by electric coupling and magnetic coupling.It has more small circuit size compared to other presented structures and it has high selectivity.Next,it presented a embedded cross coupling bandpass filter by stepped impedance resonators (SIR’s) with meander line.This structure has 24.5% miniaturized rate compared to the structure which introduced before.Furthermore,for these miniaturized filter ,we also presented a wide stopband low pass filter to improve the performance of higher stopband,which is realized by spur line and quarter wave open stub.The spur line with open stub has wide stopband designed by spur lines and open stubs with different resonate frequencies,the -10dB bandwidth can achieve up to maximum 7GHz for this low pass filter,we can get a wide stopband and highly frequency selective bandpass filter when combine this structure to these miniaturized filters.The simulated and measured result demonstrate that the -20dB stopband bandwidth can achieve up to 12.98GHz ,while the insertion loss and selectivity of bandpass filter is kept very good.

並列關鍵字

Miniaturized ； Open loop cross-coupled ； Bandpass filter ； High selectivities ； Stepped impedance resonators (SIR’s) ； Embedded cross coupling ； Wide stopband ； Spur line ； Quarter wave open stub

參考文獻

[1] J.C.Maxwell, “A Treatise on Electricity and Magnetism”, Dover, N.Y., 1954.

[2] David M. Pozar , Microwave engineering 3rd, USA: John Wiley & Sons, 2004, pp.389-416.

[4] Jia-Sheng Hong and M. J. Lancaster, “Couplings of Microstrip Square Open-Loop Resonators for Cross-Coupled Planar Microwave Filters,” IEEE Trans Microwave Theory Tech, vol. 44, no. 12, pp. 2099-2109, Dec. 1996.

[5] Jia-Sheng Hong and M. J. Lancaster, "Compact Microwave Elliptic Function Filter Using Novel Microstrip Meander Open-Loop Resonators," Electronics Letters, vol. 32, no. 6, pp. 563-564, Mar. 1996.

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

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具高頻率選擇性與寬截止頻帶之縮小化帶通濾波器

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