1 Design of a Tri-band Bandpass Filter Using Asymmetric SIRs for GSM,WiMAX and WLAN Applications 指導教授：管鴻 教授 學生：蘇奕昕

2 目錄  動機  非對稱步階式阻抗共振器特性  實驗結果與討論  結論  參考文獻

3 動機  Multiple service technology is widely used to enhance the performance of the radio frequency (RF) devices in modern wireless communication systems. GPS Internet GSM

4 非對稱步階式阻抗共振器特性 R=Z 2 /Z 1 共振條件 : 其中 非對稱步階式阻抗共振器示意圖

5 實驗結果與討論  The proposed tri-band filter is designed at 1.8(GSM), 3.5(WiMAX) and 5.2GHz(WLAN) basically composed of two asymmetric SIRs and a pair of enhanced couple structures. The BPF is fabricated on the substrates of Duroid 5880 with dielectric constant ε r = 2.2, loss tangent δ = and thickness h = mm.

6 實驗結果與討論  It is clearly observed that the appearance of transmission zeros aside the second passband can be adjusted by the lengths of two enhanced coupling structure.

7 實驗結果與討論  The first passband is properly determined while and G1=0.5 mm and L is fixed at 15.5 mm.

8 實驗結果與討論  The measured results show the return loss |S 11 | of 20 dB, insertion loss |S 21 | of 1.8 dB and FBW= 11.1 % at 1.8 GHz, |S 11 | of 10 dB, |S 21 | of 2.8 dB and FBW = 6.2 % at 3.5 GHz and |S 11 | of 14 dB, |S 21 | of 1.9 dB and FBW = 6.1 % at 5.2 GHz.

9 結論  A tri-band bandpass filter is proposed by using two asymmetric SIRs.  Three passbands are achieved by properly selecting the length ratio (α) and impedance ratio (R) of asymmetric SIRs.  The performance are well tuned by the lengths of two enhanced coupling structure and gap of two asymmetric SIRs.

10 參考文獻 [1] M. H. Weng, H. W. Wu, and Y. K. Su, “Compact and low loss dual-band bandpass filter using pseudo-interdigital stepped impedance resonators for WLANs,” IEEE Microw. Wireless Compon. Lett., vol. 17, no. 3, pp. 187– 189, Mar [2] M. H. Weng, H. W. Wu, K. Shu, R. Y. Yang, and Y. K. Su, “A novel tri- band bandpass filter using multilayer-based substrates for WiMAX,” 2007 European Microwave Conference (EuMC), Munich, Germany. [3] Y. C. Chang, C. H. Kao, M. H. Weng and R. Y. Yang, “Design of the compact wideband bandpass filter with low loss, high selectivity and wide stopband,” IEEE Microw. Wireless Compon. Lett., vol. 18, no. 12, pp , Dec [4] George L. Matthaei, Leo Young, E. M. T. Jones, “Microwave filters, impedance-matching networks, and coupling structures.” McGraw-Hill, New York. [5] J. S. Hong and M. J. Lancaster, Microstrip Filter for RF/Microwave Application. New York: Wiley, 2001.