A microstrip tri-band bandpass filter (BPF) based on three embedded bending stub resonators (EBSRs) is proposed in this paper. Three resonant paths that resonate at three different frequencies can achieve three passbands. The lumped circuit models of the proposed filter are given for designing. The filter is extremely compact, whose area is about 0.047λg×0.12λg. There are two transmission zeros located between the first two passbands and a transmission zero between the second and third passbands, which results in good selectivity. For demonstrating the proposed filter structure, a filter at 0.9/2.14/3.6 GHz is designed and fabricated. The measured results are well agreed with simulated ones, which indicate the validity.
2. Chen, Z.-X., X.-W. Dai, and C.-H. Liang, "Novel dual-mode dual-band bandpass filter using double square-loop structure," Progress In Electromagnetics Research, Vol. 77, 409-416, 2007.
doi:10.2528/PIER07082803
3. 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
4. Wu, Y., Y. Liu, and S. Li, "Dual-band modified Wilkinson power divider without transmission line stubs and reactive components," Progress In Electromagnetics Research, Vol. 96, 9-20, 2009.
doi:10.2528/PIER09072109
5. Wang, J., H. Ning, Q. Xiong, M. Li, and L.-F. Mao, "A novel miniaturized dual-band bandstop filter using dual-plane defected structures," Progress In Electromagnetics Research, Vol. 134, 397-417, 2013.
6. Panda, J. R. and R. S. Kshetrimayum, "A printed 2.4 GHz/5.8 GHz dual-band monopole antenna with a protruding stub in the ground plane for WLAN and RFID applications," Progress In Electromagnetics Research, Vol. 117, 425-434, 2011.
7. Lee, C.-H., C.-I. G. Hsu, and H.-K. J. huang, "Design of a new tri-band microstrip BPF using combined quarter-wavelength SIRs," IEEE Microw. Wireless Compon. Lett., Vol. 16, No. 11, 594-596, 2006.
doi:10.1109/LMWC.2006.884902
8. Chen, F. C. and Q. X. Chu, "Design of compact tri-band bandpass filters using assembled resonators," IEEE Microw. Theory Tech., Vol. 57, No. 1, 165-171, 2009.
doi:10.1109/TMTT.2008.2008963
9. 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, 2008.
doi:10.1109/LMWC.2007.911976
10. 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, 2011.
doi:10.1109/TMTT.2011.2123106
11. Wang, L. and B.-R. Guan, "Compact and high selectivity tri-band BPF using nested DDGSRs," Electron. Lett., Vol. 48, No. 7, 378-379, 2012.
doi:10.1049/el.2012.0118
12. Doan, M. T., W.Q. Che, and W.J. Feng, "Tri-band bandpass filter using square ring short stub loaded resonators," Electron. Lett., Vol. 48, No. 2, 106-107, 2012.
doi:10.1049/el.2011.3393
13. Zhang , Z., et al., "Design of a compact dual-band bandpass filter using opposite hook-shaped resonator," IEEE Microw. Wireless Compon. Lett, Vol. 21, No. 7, 359-361, 2011.
doi:10.1109/LMWC.2011.2156777
14. Wadell, B. C., Transmission Line Design Handbook, Artech House, Inc., Norwood, MA, 1991.
15. Liu, Y., W.-B. Dou, and Y.-J. Zhao, "A tri-band bandpass filter realized using tri-mode T-shape branches," Progress In Electromagnetics Research, Vol. 105, 425-444, 2010.
doi:10.2528/PIER10010902
16. Chen, W.-Y. , M.-H. Weng, S.-J. Chang, and , "A new tri-band bandpass filter for GSM, WIMAX and ultra-wideband responses by using asymmetric stepped impedance," Progress In Electromagnetics Research, Vol. 124, 365-381, 2012.
doi:10.2528/PIER11122010
17. Wu, M.-S., Y.-Z. Chueh, J.-C. Yeh, and S.-G. Mao, "Synthesis of triple-band and quad band bandpass -filters using lumped-element coplanar waveguide resonators," Progress In Electromagnetics Research B, Vol. 13, 433-451, 2009.
doi:10.2528/PIERB09021302
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