本文為實現極寬頻濾波器，利用微帶線至共平面波導的耦合達到寬頻的目 的，由於傳輸線特性具週期性，故高頻頻帶會出現週期性假性通帶，相較一般 之極寬頻濾波器設計，大多以設計通帶為主，本文亦將高頻之截止頻率視為一 個設計重點。本文設計帶止與低通濾波器，其寬截止頻帶能消除高頻週性通 帶，以抑制輸入輸出結構因週期性特性在高頻所產生之假性諧波，並利用金屬 貫孔作為串接的方式，達到具寬截止頻之極寬頻濾波器。
串接之低通與帶止濾波器的設計中，由於設計自由度多，本文考量兩大因 素：|S11|與|S21|分別在通帶與截止頻帶之最大值、3 dB 頻率點之調整。傳輸零 點之位置則因上述考量訂定電路尺寸後即被確定。利用理論值與模擬值進行比 較，由於高頻之截止頻帶深度與理論值有差距，故納入為設計條件。由於電路 串接後之響應與個別設計時之響應有差異，故需利用電磁模擬軟體輔助，並觀 察串接後之整體響應，以達到極寬頻之寬截止頻濾波器之特性。
本文亦實作三個電路並加以量測，其頻寬吻合規格。雖整體損耗較模擬 高，亦證明電路結構之可行性。此外，本文三個電路之低頻通帶選擇性較差；
若欲達到較好的頻帶選擇性，可於低頻通帶附近創造一零點，或改變本文架 構。且高頻之輻射損耗較模擬值高，其原因除了實作技術外，也與耦合結構在 高頻所產生之諧波有關，因此如何提高低頻頻帶選擇性與改善輻射損耗亦為本 設計未來需要考量之重要課題。
本論文之電路架構仍可用其他具有寬截止頻帶之濾波器取代中間的串接 電路，而輸出輸入耦合結構亦可利用夾心帶線、低溫共燒陶瓷等取代共平面波 導，除可產生寬頻通帶之外，亦能抑制高頻之輻射損耗。
最後，與其他文獻所提出之濾波器比較結果，本文所提出之電路擁有寬截
止頻的效果較其他文獻所提之電路佳。
附錄一 雙埠網路的奇偶模分析
[ ]
參考文獻
[1] Revision of Part 15 of the Commission’s Rules Regarding UltraWideband Transmission System, Federal Communications Commission, 2006 [Online].
Available: http://ftp.fcc.gov/oet/info/rules/part15
[2] H. Ishida and K. Araki, “Design and analysis of UWB bandpass filter with ring filter,” in IEEE MTT-S Int. Microwave Symp. Dig., pp. 1307–1310, Jun. 2004.
[3] L. Zhu, S. Sun and W. Menzel, “Ultra-wideband (UWB) bandpass filters using multiple mode resonator,” IEEE Microw. Wireless Compon. Lett., vol. 15, no. 11, pp. 796–798, Nov. 2005.
[4] H. Wang and L. Zhu , "Aperture-backed microstrip line multiple-mode resonator for design of a novel UWB bandpass filter," Proc. Asia-Pacific Microwave Conf., vol.4, no.4, pp. 4-7, Dec. 2005.
[5] H. Shaman and J.-S. Hong , "A novel ultra-wideband (UWB) bandpass filter (BPF) with pairs of transmission zeroes," IEEE Microw. Wireless Compon. Lett., vol. 17, no. 2, pp. 121-123, Feb. 2007.
[6] C.-P. Chen, Z. Ma and T. Anada, "Synthesis of UWB bandpass filter by multistage of one-wavelength commensurate SIRs," IEEE on ICMMT Int.
Microw. Millimeter Wave Tech. Conf. , vol. 3, pp. 1247-1250, Apr. 2008.
[7] C.-P. Chen, Z. Ma, H. Nihei and T. Anada, “Novel compact ultrawideband bandpass filter with steep skirt selectivity,” in Proc. 38th Eur.
Micro. Conf., pp. 849–852, Oct. 2008.
[8] P.-K. Singh, S. Basu and Y.-H. Wang, “Planar ultra-wideband bandpass filter using edge coupled microstrip lines and stepped impedance open stub,”
IEEE Microw. Wireless Compon. Lett., vol. 17, no. 9, pp. 649–651, Sep. 2007.
[9] P. Cai , Z. Ma , X. Guan , X. Yang ,Y. Kobayashi, T. Anada and G. Hagiwara, "A compact UWB bandpass filter using two-section open-circuited stubs to realize
transmission zeros," Proc. Asia-Pacific Microwave Conf., vol. 5, no. 4 , pp.
4-7, Dec. 2005.
[10] H. Wang, L. Zhu and W. Menzel, “Ultra-wideband bandpass filter with hybrid microstrip/CPW structure,” IEEE Microw. Wireless Compon. Lett., vol. 15, no.
12, pp. 844–846, Dec. 2005.
[11] J. Gao, L. Zhu, W. Menzel and F. Bogelsack, “Short-circuited CPW multiple-mode resonator for ultra-wideband (UWB) bandpass filter,” IEEE Microw. Wireless Compon. Lett., vol. 16, no. 3, pp. 104–106, Mar. 2006.
[12] T. Kuo, S. Lin and C.-H. Chen, “Compact ultra-wideband bandpass filters using composite microstrip-coplanar-waveguide structure,” IEEE Trans. Microw.
Theory Tech., vol. 54, no. 10, pp. 3772–3778, Dec. 2000.
[13] C.-L. Hsu, F.-C. Hsu and J.-T. Kuo, “Microstrip bandpass filter for ultra-wideband (UWB) wireless communications,” IEEE MTT-S Int. Microwave Symp. Dig., pp. 679–682, Jun. 2005.
[14] R. Li and L. Zhu, “Compact UWB bandpass filter using stub-loaded multiple-mode resonator,” IEEE Microw. Wireless Compon. Lett., vol. 17, no. 1, pp. 40 – 42, Jan. 2007.
[15] T. Yasuzumi, T. Uwano and O. Hashimoto , "A study on the UWB BPF using the hairpin-type LPF and the parallel-coupled lines," Proc. Asia-Pacific Microwave Conf, pp. 2557-2560, Dec. 2009.
[16] S. Sun and L. Zhu , "Capacitive-ended interdigital coupled lines for UWB bandpass filters with improved out-of-band performances," IEEE Microw.
Wireless Compon. Lett, vol. 16, no. 8, pp. 440-442, Aug. 2006.
[17] P. Mondal, M.-K. Mandal and A. Chakrabarty, "Compact ultra-wideband bandpass filter with improved upper stopband," IEEE Microw. Wireless Compon.
Lett, vol. 17, no. 9, pp. 643-645, Sep. 2007.
[18] S.-W. Wong and L. Zhu, “EBG-embedded multiple-mode resonator for UWB bandpass filter with improved upper-stopband performance,” IEEE Microw.Wireless Compon. Lett., vol. 17, no. 6, pp. 421–423, Jun. 2007.
[19] S.-W. Wong and L. Zhu, "Ultra-wideband (UWB) microstrip bandpass filters with improved upper-stopband and miniaturized size," Proc. Asia-Pacific Microwave Conf, vol. 1, no. 4, pp. 11-14 , Dec. 2007.
[20] S.-W. Wong and L. Zhu, "Quadruple-mode UWB bandpass filter with improved out-of-band rejection," IEEE Microw.Wireless Compon. Lett.,vol. 19, no. 3, pp. 152-154, Mar. 2009.
[21] S.-W. Wong , S. Sun, L. Zhu and Z.- N. Chen , "Ultra-wideband (UWB) bandpass filters with improved upper-stopband performance,"Proc. Asia-Pacific Microwave Conf, vol. 29, no. 32, pp. 12-15, Dec. 2006.
[22] A. Abdel-Rahman , A. Balalem , J. Machac and A. Omar, "UWB bandpass filter with wide stopband using lumped coupling capacitors," Proc. Asia-Pacific Microwave Conf, vol. 7, no. 10, pp. 949-952, Dec. 2009.
[23] A.-M. Abbosh, "Planar bandpass filters for ultra-wideband applications," IEEE Trans. Microw. Theory Tech., vol. 55, no. 10, pp. 2262-2269, Oct. 2007.
[24] T.-H. Duong and I.-S. Kim, "New elliptic function type UWB BPF based on capacitively coupled open T resonator," IEEE Trans. Microw. Theory Tech., vol. 57, no. 12, pp. 3089-3098, Dec. 2009.
[25] J.-A. Ruiz-Cruz, Y. Zhang, K.-A. Zaki, A.-J. Piloto and J. Tallo,
"Ultra-wideband LTCC ridge waveguide filters,"IEEE Microw.Wireless Compon.
Lett.,vol.17, no.2, pp. 115-117, Feb. 2007
[26] W. Chen, X. Guo, B. Cao, X. Zhang, B. Wei, Y. Zhang and X. Lu, "A superconducting microstrip ultra-wideband (UWB) bandpass filter at VHF-band," IEEE Microw.Wireless Compon. Lett., vol.19, no.10, pp. 635-637, Oct. 2009.
[27] C.-Y. Liu, Q.-X. Chu and J.-Q. Huang, "An UWB filter using a novel coplanar-waveguide-based composite right/left-handed transmission line structure," Proc. Asia-Pacific Microwave Conf, vol.7, no.10, pp. 953-955, Dec.
2009.
[28] T.-B. Lim and L. Zhu , "Differential-mode ultra-wideband bandpass filter on microstrip line," Electron Lett. , vol.45, no.22, pp. 1124-1125, Oct. 2009.
[29] M.-Y. Hsieh and S.-M. Wang, "Compact and wideband microstrip bandstop filter," IEEE Microw. Wireless Compon. Lett., vol.15, no.7, pp. 472- 474, Jul.
2005.
[30] V.-K. Velidi, A.-B. Guntupalli and S. Sanyal, "Sharp-rejection ultra-wide bandstop filters," IEEE Microw. Wireless Compon. Lett., vol.19, no.8, pp.
503-505, Aug. 2009.
[31] D. M. Pozar, Microwave Engineering, 3rd ed. New York: Wiley 2003.
[32] G. L. Matthaei, L. Young and E. M. T. Jones, Microwave Filters, Impedance-Matching Networks, and Coupling Structures. New York:
McGraw-Hill, 1964.
[33] IE3D Simulator, Zeland Software Inc., Jan. 1997.