A high-order dual-band bandpass filter using novel combined stub-loaded resonators (CSLRs) is presented in this paper. The key merits of the filter configuration are that the center frequency and also the bandwidth of each passband can be controlled conveniently. Moreover, it can build the high-order dual-band bandpass filters using the proposed resonators because of the sufficient coupling through the four symmetric stubs. A fifth-order dual-band bandpass filter designed at 2.5/3.5 GHz was built and tested. The measurement and simulation results agree very well, demonstrating the validity of the method.
2. Weng, M. H., H. W. Wu, and Y. K. Su, "Compact and low-loss dualband bandpass filter using pseudo-interdigital stepped impedance resonators for WLANs," IEEE Microw. Wirel. Compon. Lett., Vol. 17, No. 3, 187-189, 2007.
3. Chu, Q. X. and F. C. Chen, "A compact dual-band bandpass filter using meandering stepped impedance resonators," IEEE Microw. Wirel. Compon. Lett., Vol. 16, No. 11, 320-322, May 2008.
4. Hsu, Y., C. Y. Chen, and H. R. Chuang, "A miniaturized dual-band bandpass filter using embedded resonators," IEEE Microw. Wirel. Compon. Lett., Vol. 21, No. 12, 658-660, Dec. 2011.
5. Chang, W.-S. and C.-Y. Chang, "Analytical design of microstrip short-circuit terminated stepped-impedance resonator dual-band filters," IEEE Trans. Microw. Theory Tech., Vol. 59, No. 7, 1730-1739, Jul. 2011.
6. Jiang, M., L.-M. Chang, and A. Chin, "Design of dual-passband microstrip bandpass filters with multi-spurious suppression," IEEE Microw. Wirel. Compon. Lett., Vol. 20, No. 4, 199-201, Apr. 2010.
7. Mondal, P. and M. K. Mandal, "Design of dual-band bandpass filters using stub-loaded open-loop resonators," IEEE Trans. Microw. Theory Tech., Vol. 56, No. 1, 150-155, Jan. 2008.
8. Chen, F.-C. and Q.-X. Chu, "Novel multistub loaded resonator and its application to high-order dual-band filters," IEEE Trans. Microw. Theory Tech., Vol. 58, 1551-1556, Jun. 2010.
9. Ma, D., Z. Y. Xiao, L. Xiang, X. Wu, C. Huang, and X. Kou, "Compact dual-band bandpass filter using folded SIR with two stubs for WLAN," Progress In Electromagnetics Research, Vol. 117, 357-364, 2011.
10. Chen, C.-H., C.-S. Shih, T.-S. Horng, and S.-M. Wu, "Very miniature dual-band and dual-mode bandpass filter designs on an integrated passive device chip," Progress In Electromagnetics Research, Vol. 119, 461-476, 2011.
11. Chen, C.-Y. and C.-C. Lin, "The design and fabrication of a highly compact microstrip dual-band bandpass filter," Progress In Electromagnetics Research, Vol. 112, 299-307, 2011.
12. Yang, R.-Y., H. Kuan, C.-Y. Hung, and C.-S. Ye, "Design of dual-band bandpass filters using a dual feeding structure and embedded uniform impedance resonators," Progress In Electromagnetics Research, Vol. 105, 93-102, 2010.
13. Chiou, Y.-C., P.-S. Yang, J.-T. Kuo, and C.-Y.Wu, "Transmission zero design graph for dual-mode dual-band filter with periodic stepped-impedance ring resonator," Progress In Electromagnetics Research, Vol. 108, 23-36, 2010.
14. Chin, K.-S. and C.-K. Lung, "Miniaturized microstrip dual-band bands-stop filters using tri-section stepped impedance resonators," Progress In Electromagnetics Research C, Vol. 10, 37-48, 2009.
15. Chen, F.-C. and J.-M. Qiu, "Dual-band bandpass filter with control-lable characteristics using stub-loaded resonators," Progress In Electromagnetics Research Letters, Vol. 28, 45-51, 2012.
16. Wang, X.-H., B.-Z. Wang, and K.-J. Chen, "Compact broadband dual-band bandpass filters using slotted ground structures Progress In Electromagnetics Research,", Vol. 82, 151-166, 2008.
17. Xiao, J.-K. and H.-F. Huang, "New dual-band bandpass filter with compact SIR structure," Progress In Electromagnetics Research Letters, Vol. 18, 125-134, 2010.
18. Luo, S., L. Zhu, and S. Sun, "A dual-mode dual-band bandpass filter using a single slot ring resonator," Progress In Electromagnetics Research Letters, Vol. 23, 173-180, 2011.
19. Vegesna, S. and M. A. Saed, "Novel compact dual-band bandpass microstrip filter," Progress In Electromagnetics Research B, Vol. 20, 245-262, 2010.