This paper presents a novel approach for designing planar multimode wideband bandpass filters with good selectivity. The multimode resonator is composed of an open-ended microstrip line with length of half-wavelength (λ/2) and several radial-line stubs. By using different kinds of radial-line stub-loaded, different kinds of responses including three-pole and four-pole bandpass filters can be realized. Depending on electric field distribution and equivalent circuit model, the characteristics of the filter are analyzed. To verify the proposed method, two filters are implemented. The measured results exhibit good agreement with the simulation.
"Novel Planar Multimode Bandpass Filters with Radial-Line Stubs," Progress In Electromagnetics Research,
Vol. 101, 33-42, 2010. doi:10.2528/PIER09121303
1. 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
2. Xiao, J.-K., Q.-X. Chu, and H.-F. Huang, "Novel microstrip right-angled triangular patch resonator bandpass filter," Journal of Electromagnetic Waves and Applications, Vol. 22, No. 4, 581-591, 2008. doi:10.1163/156939308784150227
3. Wang, J.-P., L. Wang, Y.-X. Guo, Y. X. Wang, and D.-G. Fang, "Miniaturized dual-mode bandpass filter with controllable harmonic response for dual-band applications," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 11--12, 1525-1533, 2009. doi:10.1163/156939309789476482
4. Zhao, L.-P., C.-H. Liang, G. Li, and X.-W. Dai, "Novel design of dual-mode bandpass filter with triangular structure," Journal of Electromagnetic Waves and Applications, Vol. 22, No. 7, 923-932, 2008. doi:10.1163/156939308784150146
5. Wu, G.-L., W. Mu, X.-W. Dai, and Y.-C. Jiao, "Design of novel dual-band bandpass filter with microstrip meander-loop resonator and CSRR DGS," Progress In Electromagnetics Research, Vol. 78, 17-24, 2008. doi:10.2528/PIER07090301
6. Mo, S.-G., Z.-Y. Yu, and L. Zhang, "Compact dual-mode bandpass filters using hexagonal meander loop resonators," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 13, 1723-1732, 2009. doi:10.1163/156939309789566941
7. Zhao, L.-P., X. Zhai, B. Wu, T. Su, W. Xue, and C.-H. Liang, "Novel design of dual-mode bandpass filter using rectangle structure," Progress In Electromagnetics Research B, Vol. 3, 131-141, 2008. doi:10.2528/PIERB07121003
8. Serrano, A. L. C. and F. S. Correra, "A triple-mode bandpass filter using a modified circular patch resonator," Microw. Opt. Technol. Lett., Vol. 51, No. 1, 178-182, 2009. doi:10.1002/mop.23950
9. Hong, J.-S. and M. J. Lancaster, Microstrip Filters for RF/Microwave Applications, Wiley, New York, 2001.
11. Zhu, L. and W. Menzel, "Compact microstrip bandpass filter with two transmission zeros using a stub-tapped half-wavelength line resonator," IEEE Microw. Wireless Compon. Lett., Vol. 13, No. 1, 16-18, 2003. doi:10.1109/LMWC.2002.807705
12. Amari, S., K. Hamed, Y. Antar, and A. Freundorfer, "New elliptic microstrip λ/4-resonator filters," Proc. Asia-Pacific Microw. Conf., 755-758, 2001.
13. Li, L., Z.-F. Li, and Q.-F. Wei, "A quasi-elliptic wideband bandpass ¯lter using a novel multiple-mode resonator constructed by an asymmetric compact microstrip resonant cell," Microw. Opt. Technol. Lett., Vol. 51, No. 3, 713-714, 2009. doi:10.1002/mop.24168
14. Giannini, F., R. Sorrentino, and J. Vrba, "Planar circuit analysis of microstrip radial stub," IEEE Trans. Microw. Theory Tech., Vol. 32, No. 12, 1652-1655, 1984. doi:10.1109/TMTT.1984.1132907
15. Ma, K., K. S. Yeo, and Q. Sun, "A novel planar multimode bandpass filter with radial perturbation," Microw. Opt. Technol. Lett., Vol. 51, No. 4, 964-966, 2009. doi:10.1002/mop.24258