A novel microstrip quad-band bandpass filter was designed and fabricated on an Al2O3 ceramic substrate of 1 mm thick. Two different types of open-loop resonator --- a winding line-shaped resonator (WLR) and a stepped impedance resonator (SIR) --- were positioned in parallel at the two sides of input/output microstrip lines that had the same coupling lengths and coupling gap widths. The proposed filter was based on a WLR with four different resonant frequencies: 1.23 GHz, 2.49 GHz, 3.73 GHz, and 5.41 GHz. By carefully selecting the resonant frequencies of the two resonators to be slightly different, the phase difference for the signals in the two resonators was negative, indicating that energy cancellation occurred, resulting in wide bandwidths and deep transmission zeros. The spurious resonant frequencies of the SIR were designed to be non-integer multiples of the fundamental resonant frequency by adjusting the length, characteristic impedance ratio, and electrical length. The SIR was designed to have three resonant frequencies at around 2.27 GHz, 3.37 GHz, and 4.94 GHz, which had phase differences with the WLR's resonant frequencies of 2.49 GHz, 3.73 GHz, and 5.41 GHz. Finally, a novel quad-band filter with a narrow band in the L2-band (GPS, 1.227 GHz) and three wide bands in the WIMAX (3.5 GHz) and WLAN (2.4 GHz and 5.2 GHz) was achieved.
"Design and Fabrication of a Compact Quad-Band Bandpass Filter Using Two Different Parallel Positioned Resonators," Progress In Electromagnetics Research,
Vol. 115, 159-172, 2011. doi:10.2528/PIER11022108
1. Yang, G. M., R. Jin, C. Vittoria, V. G. Harris, and N. X. Sun, "Small ultra-wideband (UWB) bandpass filter with notch band," IEEE Microwave Wireless Compoents Letters, Vol. 18, No. 3, 176-178, 2008. doi:10.1109/LMWC.2008.916781
2. Zhou, Y. and S. Lucyszyn, "Modelling of reconfigurable terahertz integrated architecture (Retina) SIW structures," Progress In Electromagnetics Research, Vol. 105, 71-92, 2010. doi:10.2528/PIER10041806
3. Yin, Q., L.-S. Wu, L. Zhou, and W.-Y. Yin, "Compact dual-band bandpass filter using asymmetrical dual stub-loaded open-loops," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 17--18, 2397-2406, 2010. doi:10.1163/156939310793675718
4. 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.
5. Wen, S. and L. Zhu, "Numerical synthesis design of coupled resonator filters," Progress In Electromagnetics Research, Vol. 92, 333-346, 2009. doi:10.2528/PIER09041102
6. Hu, G., C. Liu, L. Yan, K. Huang, and W. Menzel, "Novel dual mode substrate integrated waveguide band-pass filters," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 11--12, 1661-1672, 2010. doi:10.1163/156939310792149768
7. 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
8. Chen, W.-N. and W.-K. Chia, "A novel approach realizing 2.4/5.2 GHz dual-band BPFs using twin-spiral etched ground structure," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 7, 829-840, 2009. doi:10.1163/156939309788355261
9. 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.
10. Chen, C. F., T. Y. Huang, and R. B. Wu, "Design of dual- and triple-passb and filters using alternately cascaded multiband resonators," IEEE Trans. Microw. Theory Tech., Vol. 54, No. 9, 3550-3558, 2006. doi:10.1109/TMTT.2006.880653
11. Goudos, S. K., Z. D. Zaharis, and T. Yioultsis, "Application of a differential evolution algorithm with strategy adaptation to the design of multi-band microwave filters for wireless communications," Progress In Electromagnetics Research, Vol. 109, 123-137, 2010. doi:10.2528/PIER10081704
12. Cheng, C. M. and C. F. Yang, "Develop quad-band (1.57/2.45/3.5/5.2 GHz) bandpass filters on the ceramic sub-strate," IEEE Microwave Wireless Components Letters, Vol. 20, No. 5, 268-270, 2010. doi:10.1109/LMWC.2010.2045585
13. Rosenberg, U. and S. Amari, "Novel coupling schemes for microwave resonator filters," IEEE Trans. Microwave Theory Tech, Vol. 50, 2896-2902, Dec. 2002. doi:10.1109/TMTT.2002.805171
14. Rebenaque, D. C., F. Q. Pereira, J. P. García, A. A. Melcón, and M. Guglielmi, "Two compact configurations for implementing transmission zeros in microstrip filters," IEEE Microwave Wireless Components Letters, Vol. 14, No. 10, 475-477, 2004. doi:10.1109/LMWC.2004.834564
15. Osipenkov, V. and S. G. Vesnin, "Microwave filters of parallel cascade structure," IEEE Trans. Microwave Theory Tech., Vol. 42, 1360-1367, 1994. doi:10.1109/22.299730
16. Makimoto, M. and S. Yamashita, "Bandpass filters using parallel coupled stripline stepped impedance resonators," IEEE Trans. Microw. Theory Tech., Vol. 28, No. 12, 1413-1417, 1980. doi:10.1109/TMTT.1980.1130258
17. Hong, J. S. and M. J. Lancaster, Microstrip Filters for RF/Microwave Applications, Wiley, New York, 2001. doi:10.1002/0471221619
18. Kung, C.-Y., Y.-C. Chen, S.-M. Wu, C.-F. Yang, and J.-S. Sun, "A novel compact 2.4/5.2 GHz dual wideband bandpass filter with deep transmission zero," Journal of Electromagnetic Waves and Applications, Vol. 25, No. 5--6, 617-628, 2011. doi:10.1163/156939311794827168
19. Yang, C. F., M. Cheung, C. Y. Huang, and J. S. Sun, "Print a compact single- and quad-band slot antenna on ceramic substrate," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 13, 1697-1707, 2010.