volume | PIER Journals

Abstract

Stub-loaded step-impedance resonator (SLSIR) is a multi-mode resonator and can be applied to implement multi-band or wideband filters. In this paper, odd- and even mode impedance analysis is used to resonant properties of the SLSIR. Only two SLSIRs are applied to design a quint-band bandpass filter (BPF). To find the required five resonant modes, the frequency ratios of the high order modes to the fundamental mode of the SLSIR are calculated depending on the impedance ratio and the length ratio of the SLSIR. Several coupling types of the SLSIRs are considered first to have enough energy for all the five passbands. When forming the quint-band, a pair of the SLSIR are coupled electrically and connected with 0o feeding input/output structure. The center frequencies are designed at 1.38 GHz, 2.58 GHz, 3.69 GHz, 5.36 GHz, and 5.8 GHz, corresponding to the different communication applications. The filter is designed, fabricated, and measured. Simulated and experimental results are in agreement, verifying the design concept.

1. Luo, S., L. Zhu, and S. Sun, "Compact dual-mode triple-band bandpass filters using three pairs of degenerate modes in a ring resonator," IEEE Trans. Microw. Theory Tech., Vol. 59, No. 5, 1222-1229, May 2011.
doi:10.1109/TMTT.2011.2123106

2. Chen, W. Y., S. J. Chang, M. H. Weng, Y. H. Su, and H. Kuan, "Simple method to design a tri-band bandpass filter using asymmetric SIRs for GSM, WiMAX and WLAN applications," Microwave Opt. Tech. Lett., Vol. 53, No. 7, 1573-1576, Jul. 2011.
doi:10.1002/mop.26037

3. Chen, W. Y., M. H. Weng, and S. J. Chang, "A new tri-band bandpass filter based on stub-loaded stepped impedance resonator," IEEE Microw. Wireless Compon. Lett., Vol. 22, 179-181, Apr. 2012.
doi:10.1109/LMWC.2012.2187884

4. Chen, C. F., T. Y. Huang, and R. B. Wu, "Design of dual- and triple-passband filters using alternately cascaded multiband resonators," IEEE Trans. Microw. Theory Tech., Vol. 54, No. 9, 3550-3558, Sep. 2006.
doi:10.1109/TMTT.2006.880653

5. 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 Microw. Wireless Compon. Lett., Vol. 18, No. 1, 19-21, Jan. 2008.
doi:10.1109/LMWC.2007.911976

6. Chen, F. C. and Q. X. Chu, "Design of compact quad-band bandpass filters using assembled resonators," Microwave Opt. Tech. Lett., Vol. 53, No. 6, 1305-1308, Jun. 2011.
doi:10.1002/mop.25993

7. Hsu, K. W., W. C. Hung, and W. H. Tu, "Compact quint-band microstrip bandpass filter using double-layered substrate," IEEE MTT-S Int. Microw. Symp. Dig., Vol. 7, No. 6, 1041-1044, Jun. 2013.

8. Chen, C. F., "Design of a compact microstrip quint-band filter based on the tri-mode stub-loaded stepped- impedance resonators," IEEE Microw. Wireless Compon. Lett., Vol. 22, No. 7, 357-359, Jul. 2012.
doi:10.1109/LMWC.2012.2202894

9. Chen, L. and F. Wei, "Compact quad-and quint-band BPFs based on multimode stub loaded resonators," Microwave Opt. Tech. Lett., Vol. 57, No. 12, 2837-2841, Dec. 2015.
doi:10.1002/mop.29438

10. Xu, J., W. Wu, and G. Wei, "Compact multi-band bandpass filters with mixed electric and magnetic coupling using multiple-mode resonator," IEEE Trans. Microw. Theory Tech., Vol. 63, No. 12, 3909-3920, Dec. 2015.
doi:10.1109/TMTT.2015.2488643

11. Zhu, C. M., J. Xu, W. Kang, and W. Wu, "Compact QB-BPF based on single PMR," Electronics Lett., Vol. 52, No. 17, 1463-1465, 2016.
doi:10.1049/el.2016.2202

12. Ai, J., Y. Zhang, K. D. Xu, D. Li, and Y. Fan, "Miniaturized quint-band bandpass filter based on multi-mode resonator and λ/4 resonators with mixed electric and magnetic coupling," IEEE Microw. Wireless Compon. Lett., Vol. 26, No. 5, 343-345, May 2016.
doi:10.1109/LMWC.2016.2549643

13. Zhou, K., C. X. Zhou, H. W. Xie, and W. Wu, "Synthesis design of SIW multiband bandpass filters based on dual-mode resonances and split-type dual- and triple-band responses," IEEE Trans. Microw. Theory Tech., Vol. 67, No. 1, 151-161, Jan. 2019.
doi:10.1109/TMTT.2018.2874250

14. Hong, J. S., Microstrip Filters for RF/Microwave Applications, 2nd Ed., Wiley, 2011.
doi:10.1002/9780470937297

15. IE3D Simulator; Zeland Software, Inc., CA, USA, 2002.

16. Tsai, C. M., S. Y. Lee, and C. C. Tsai, "Performance of a planar filter using a 0^◦ feed structure," IEEE Trans. Microw. Theory Tech., Vol. 50, No. 10, 2362-2367, Nov. 2002.
doi:10.1109/TMTT.2002.803421

Dr. Liqin Liu

Dr. Min-Hang Weng

Dr. Yabin Weng

Dr. Chin-Yi Tsai

Professor Ru-Yuan Yang