volume | PIER Journals

Abstract

This paper presents a novel compact microstrip hybrid four-mode bandpass filter (BPF) with good selectivity and multi-transmission zeros. By adding an external resonator to a triple-mode stub-loaded uniform impedance resonator, four modes are generated in the desired passband and a hybrid four-mode BPF is implemented. Even- and odd-mode theory is introduced to investigate the mode characteristics of triple-mode resonator in detail. Circuit model and coupling matrix are built to further explain the proposed methodology. A microstrip BPF with central frequency of 3.4 GHz for wireless communication was designed and fabricated. Three transmission zeros are obtained at 3.2 GHz, 3.55 GHz and 3.73 GHz, which improve selectivity and out-of-band rejection of the filter. The measured results of the fabricated filter represent good in-band and sharp sideband characteristic, which match well with simulated results.

1. Wolff, I., "Microstrip bandpass filter using degenerate modes of Microstrip bandpass filter using degenerate modes of," Electronics Letters, Vol. 8, No. 12, 302-303, 1972.
doi:10.1049/el:19720223

2. 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

3. Athukorala, L. and D. Budimir, "Design of open-loop dual-mode microstrip filters," Progress In Electromagnetics Research Letters , Vol. 19, 179-185, 2010.

4. Deng, H.-W., Y.-J. Zhao, X.-S. Zhang, L. Zhang, and W. Zhao, "Compact dual-mode open stub-loaded resonator and BPF," Progress In Electromagnetics Research Letters, Vol. 14, 119-125, 2010.
doi:10.2528/PIERL10032904

5. Guan, X., B. Wang, X. Y. Wang, S. Wang, and H. Liu, "A novel dual-mode bandpass filter using stub-loaded defected ground open-loop resonator," Progress In Electromagnetics Research Letters, Vol. 26, 31-37, 2011.
doi:10.2528/PIERL11071402

6. Shen, W., X.-W. Sun, and W.-Y. Yin, "A novel microstrip filter using three-mode stepped impedance resonator (TSIR)," IEEE Microw. Wireless Compon. Lett., Vol. 19, No. 12, 774-776, 2009.
doi:10.1109/LMWC.2009.2033495

7. Zhang, L., Z. Yu, and S. Mo, "Novel planar multimode bandpass filters with radial-line stubs," Progress In Electromagnetics Research, Vol. 101, 33-42, 2010.
doi:10.2528/PIER09121303

8. 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

9. Xiao, J.-K., Q.-X. Chu, and S. Zhang, "Novel microstrip triangular resonator bandpass filter with transmission zeros and wide bands using fractal-shaped defection," Progress In Electromagnetics Research, Vol. 77, 343-356, 2007.
doi:10.2528/PIER07081901

10. Amari, S. and U. Rosenberg, "New building blocks for modular design of elliptic and self-equalized filters," IEEE Trans. Microw. Theory Tech., Vol. 52, No. 2, 721-736, 2004.
doi:10.1109/TMTT.2003.821923

11. Liao, C.-K., P.-L. Chi, and C.-Y. Chang, "Microstrip realization of generalized Chebyshev filters with box-like coupling schemes," IEEE Trans. Microw. Theory Tech., Vol. 55, No. 1, 147-153, 2007.
doi:10.1109/TMTT.2006.888580

12. Shen, W., W. Y. Yin, X. W. Sun, and J. F. Mao, "Compact substrate integrated waveguide (SIW) transversal filter with triple-mode microstrip resonator," Proceedings of Asia-Pacific Microwave Conference, 1875-1878, 2010.

13. Zhang, X. Y., J.-X. Chen, Q. Xue, and S. M. Li, "Dual-band bandpass filters using stub-loaded resonators," IEEE Microw. Wireless Compon. Lett., Vol. 17, No. 8, 583-585, 2007.
doi:10.1109/LMWC.2007.901768

14. Amari, S., U. Rosenberg, and J. Bornemann, "Adaptive synthesis and design of resonator filters with source/load-multiresonator coupling," IEEE Trans. Microwave Theory and Tech., Vol. 50, No. 8, 1969-1977, 2002.
doi:10.1109/TMTT.2002.801348

Prof. Xuehui Guan

Dr. Xiaoyan Wang

Dr. Bin Wang

Dr. Ye Yuan

Professor Hai-Wen Liu