volume | PIER Journals

Abstract

This paper proposes a method to design an even-order symmetric bandpass filter with Chebyshev response. The alternative J inverters and λ/4 short-ended resonators are used in the filter design. It is well known that a conventional even-order Chebyshev bandpass filter prototype can be designed by using J-inverters. However, to achieve the Chebyshev response, a problem is that the output admittance YL is unequal to the input admittance Y₀ since normalized g_n+1 is not equal to the g₀. But for the symmetrical structure, an additional impedance transform can be installed at the output port to solve this problem, thus the network of even-order symmetric bandpass filter with a Chebyshev response should be modified with new J-inverters. In this work, all J-inverters of the symmetric bandpass filter with Chebyshev response are extracted and described as curves to determine the circuit dimensions of the proposed structure. Two even-order Chebyshev bandpass filters with the second- and fourth-order are designed with the proposed method as its application examples. Finally, the fourth-order filter is fabricated and measured at center frequency of 2.5 GHz with the fractional bandwidth 25%. The measured result is in good agreement with the simulated one.

1. Gao, M.-J., L.-S. Wu, and J. F. Mao, "Compact notched ultra-wideband bandpass filter with improved out-of-band performance using quasi electromagnetic band gap structure," Progress In Electromagnetics Research, Vol. 125, 137-150, 2012.
doi:10.2528/PIER12011701 Google Scholar

2. Wu, G.-L., W. Mu, X.-W. Dai, and Y.-C. Jiao, "Design of novel dual-band bandpass filter with microstrip meander-loop resonator and CSRR DGS," Progress In Electromagnetics Research, Vol. 78, 17-24, 2008.
doi:10.2528/PIER07090301 Google Scholar

3. Xiao, J.-K., Q.-X. Chu, and S. Zhang, "Novel microstrip triangular resonator bandpass filter with transmission zeros and wide bands using fractal-shaped defection," Progress In Electromagnetics Research, Vol. 77, 343-356, 2007.
doi:10.2528/PIER07081901 Google Scholar

4. Chen, Y.-M., S.-F. Chang, C.-C. Chang, and T.-J. Hung, "Design of stepped-impedance combline bandpass filters with symmetric insertion-loss response and wide stopband range," IEEE Transactions on Microwave Theory and Techniques, Vol. 55, No. 10, Oct. 2007. Google Scholar

5. Weng, M.-H., C.-Y. Hung, and Y.-K. Su, "A hairpin line diplexer for direct sequence ultra-wideband wireless communications," IEEE Microwave and Wireless Components Letters, Vol. 17, No. 7, Jul. 2007. Google Scholar

6. Tsujiguchi, T., H. Matsumoto, and T. Nishikawa, "A miniaturized end-coupled bandpass filter using hairpin coplanar resonators," IEEE MTT-S Int. Microw. Symp. Dig., Vol. 2, 829-832, 1998. Google Scholar

7. Bahrami, H., M. Hakkak, and A. Pirhadi, "Analysis and design of highly compact bandpass waveguide filter utilizing complementary split ring resonators (CSRR)," Progress In Electromagnetics Research, Vol. 80, 107-122, 2008. Google Scholar

8. Mo, S.-G., Z.-Y. Yu, and L. Zhang, "Design of triple-mode bandpass filter using improved hexagonal loop resonator," Progress In Electromagnetics Research, Vol. 96, 117-125, 2009.
doi:10.2528/PIER09080304 Google Scholar

9. Adam, H., A. Ismail, M. A. Mahdi, M. S. Razalli, A. Alhawariand, and B. K. Esfeh, "X-band miniaturized wideband bandpass filter utilizing multilayered microstrip hairpin resonator," Progress In Electromagnetics Research, Vol. 93, 177-188, 2009.
doi:10.2528/PIER09042202 Google Scholar

10. Matthaei, G., L. Young, and E. Jones, Microwave Filters, Impedance-matching Networks and Coupling Structures, Artech House, Norwood, NA, 1980.

11. Lin, S.-C. and C.-Y. Yeh, "Stopband-extended balanced filters using both λ/4 and λ/2 sirs with common-mode suppression and improved passband selectivity," Progress In Electromagnetics Research, Vol. 128, 215-228, 2012. Google Scholar

12. Hsu, C.-L. and J.-T. Kuo, "Microstrip realization of trisection synthesis with frequency-dependent admittance inverter," Progress In Electromagnetics Research, Vol. 113, 195-210, 2011. Google Scholar

13. Btlez-Lopez, D. J. M. and J. M. R.-Cortes, "Direct determination of the coe±cients of chebyshev polynomials and other consideration," 35th Midwest Symposium on Circuits and Systems, 466-468, 1992.
doi:10.1109/MWSCAS.1992.271362 Google Scholar

14. Castaldi, G., V. Fiumara, and I. Gallina, "An exact synthesis method for dual-band Chebyshev impedance transformers," Progress In Electromagnetics Research, Vol. 86, 305-319, 2008.
doi:10.2528/PIER08100605 Google Scholar

15. Lee, J. R., J. H. Cho, and S. W. Yun, "New compact bandpass filter using microstrip λ/4 resonators with open stub inverter," IEEE Microw. Guided Wave Lett., Vol. 10, No. 12, 526-527, Dec. 2000.
doi:10.1109/75.895091 Google Scholar

16. Wang, C. H., Y. S. Lin, and C. Hsiung, "Novel inductance-incorporated microstrip coupled-line bandpass filters with two attenuation poles," IEEE MTT-S Int. Microw. Symp. Dig., Vol. 3, 1979, 2004. Google Scholar

17. Lin, Y. S., C. H. Wang, C. H. Wu, and C. Hsiung, "Novel compact parallel-coupled microstrip bandpass filters with lumped element K-inverters," IEEE Transactions on Microwave Theory nd Techniques, Vol. 53, No. 7, 2324-2328, Jul. 2005. Google Scholar

18. Wu, C. H., Y. S. Lin, C. H. Wang, and C. Hsiung, "Novel microstrip coupled-line bandpass filters with shortened coupled sections for stop-band extension," IEEE Transactions on Microwave Theory and Techniques, Vol. 54, No. 2, 540-546, Feb. 2006.
doi:10.1109/TMTT.2005.862710 Google Scholar

19. Hunter, I. C., Theory and Design of Microwave Filters, The Institution of Engineering and Technology, London, UK , 2006.

20. Zhang, S. and L. Zhu, "Synthesis method for even-order symmetrical Chebyshev bandpass filters with alternative J/K inverters and λ/4 resonators," IEEE Transactions on Microwave Theory and Techniques, Vol. 61, No. 2, Feb. 2010. Google Scholar

21. Hong, J. S. and M. J. Lancaster, Microstrip Filters for RF/Microwave Applications, Wiley, New York, 2001.
doi:10.1002/0471221619

22. Makimoto, M. and S. Yamashita, Microwave Resonators and Filters for Wireless Communication, Springer-Verlag, Berlin, Heidelberg, 2001.
doi:10.1007/978-3-662-04325-7

Dr. Kai Wang

Dr. Li-Sheng Zheng

Prof. Sai Wai Wong

Dr. Yu-Fa Zheng

Prof. Qing-Xin Chu