An improved CPW-fed configurations with dual-mode double-square-ring resonators (DMDSRR) for tri-band application is proposed in this paper. The resonant frequency equations related to DMDSRR geometry are introduced for simply designing tri-band bandpass filter (BPF). Resonant frequencies and transmission zeroes can be controlled by tuning the perimeter ratio of the square rings. To obtain lower insertion loss, higher out-of-band rejection level and wider bandwidth of tri-band, the improved coplanar waveguide (CPW) fed and the step impedance resonator (SIR) and meander line dual-mode perturbations are designed. The effective design procedure is provided. The proposed filter is successfully simulated and measured. It can be applied to WLAN (2.45, 5.20 and 5.80 GHz) and WiMAX (3.50 GHz) systems.
2. Zhang, L., Z. Y. Yu, and S. G. Mo, "Dual-mode dual-band bandpass filter using an open-loop resonator," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 11-12, 1603-1609, 2009.
3. 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.
4. Guo, L., Z.-Y. Yu, and L. Zhang, "Design of a dual-mode dual-band filter using stepped impedance resonators," Progress In Electromagnetics Research Letters, Vol. 14, 147-154, 2010.
5. Zhao, H. and T. J. Cui, "Novel triple-mode resonators using split-ring resonator," Microwave Opt. Technol Lett., Vol. 49, No. 12, 2918-2922, May 2007.
6. Mokhtaari, M., J. Bomemana, K. Rambabu, and S. Amari, "Coupling matrix design of dual and triple passband filters," IEEE Trans. Microwave Theory Tech., Vol. 54, No. 11, 3940-3945, Nov. 2006.
7. Lee, J. and K. Sarabandi, "Design of triple-passband microwave filters using frequency transformations," IEEE Trans. Microwave Theory Tech., Vol. 56, No. 1, 187-193, Jan. 2008.
8. Chen, F. C., Q. X. Chu, and Z. H. Tu, "Tri-band bandpass filter using stub loaded resonators," Electronics Letters, Vol. 44, No. 12, 747-749, Jun. 2008.
9. Chen, C. F., T. Y. Huang, and R. B. Wu, "Design of dual- and triple-passband filters using alternately cascaded multiband resonators," IEEE Trans. Microwave Theory Tech., Vol. 54, No. 9, 3550-3558, Sep. 2006.
10. Lee, C. H., C. I. G. Hsu, and H. K. Jhuang, "Design of a new tri-band microstrip BPF using combined quarter-wavelength SIRs," IEEE Microw. Wireless Compon. Lett., Vol. 16, No. 11, 594-596, Nov. 2006.
11. Chu, Q. X. and X. M. Lin, "Advanced triple-band bandpass filter using tri-section SIR," Electronics Lett., Vol. 44, No. 4, 295-296, Feb. 2008.
12. Hsu, C. I. G., C. H. Lee, and Y. H. Hsieh, "Tri-band bandpass filter with sharp passband skirts designed using tri-section SIRs," IEEE Trans. Microwave Theory Tech., Vol. 18, No. 1, 19-21, Jan. 2008.
13. Chen, F. C. and Q. X. Chu, "Design of compact tri-band bandpass filters using assembled resonators," IEEE Trans. Microwave Theory Tech., Vol. 57, No. 1, 165-171, Jan. 2009.
14. Chu, Q. X., F. C. Chen, Z. Tu, and H. Wang, "A novel crossed resonator and its applications to bandpass filters," IEEE Trans. Microwave Theory Tech., Vol. 57, No. 7, 1753-1759, Jul. 2009.
15. Chen, B. J., T. M. Shen, and R. B. Wu, "Design of tri-band filters with improved band allocation," IEEE Trans. Microwave Theory Tech., Vol. 57, No. 7, 1790-1797, Jul. 2009.
16. Zhang, X. Y., Q. Xue, and B. J. Hu, "Planar tri-band bandpass filter with compact size," IEEE Microw. Wireless Compon. Lett., Vol. 20, No. 5, 262-264, May 2010.
17. Ren, L. Y., "Tri-band bandpass filters based on dual-plane microstrip/dgs slot structure," IEEE Microw. Wireless Compon. Lett., Vol. 20, No. 8, 429-431, Aug. 2010.
18. Lai, X., C. H. Liang, H. Di, and B. Wu, "Design of triband filter based on stub loaded resonator and DGS resonator," IEEE Microw. Wireless Compon. Lett., Vol. 20, No. 5, 265-267, May 2010.
19. Lin, X. M., "Design of compact tri-band bandpass filter using λ/4 and stub-loaded resonators ," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 14-15, 2029-2035, 2010.
20. Hsu, C. I. G., C. H. Lee, and H. K. Jhuang, "Design of a novel quad-band microstrip BPF using quarter-wavelength stepped-impedance resonators," Microw. J., Vol. 50, No. 2, 102-112, Feb. 2007.
21. Liu, J. C., J. W. Wang, B. H. Zeng, and D. C. Chang, "CPW-fed dual-mode double-square-ring resonators for quad-band filters," IEEE Microw. Wireless Compon. Lett., Vol. 20, No. 3, 142-144, Mar. 2010.
22. Weng, R. M. and P. Y. Hsiao, "Double-layered quad-band bandpass filter for multi-band wireless systems," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 16, 2153-2161, 2009.
23. Chang, K. and L. H. Hsieh, Microwave Ring Circuits and Related Structures, John Wiley & Sons, Inc., New Jersey, 2004.
24. Zeland Software Inc., IE3D version 10.0, Jan. 2005.