volume | PIER Journals

Abstract

A compact dual-mode open stub-loaded resonator and bandpass filter (BPF) is proposed in this paper. The resonator, which is formed by attaching a disc-shaped open stub and circular open stubs in pairs to a high impedance microstrip line, generates two operating modes in the desired band, and the even-mode resonance frequency can be flexibly controlled by the disc-shaped open stub at central plane, whereas the odd-mode one is fixed. The four transmission zeros are created to sharpen the rejection skirt, suppress two high harmonic resonant modes and deepen upper-stopband, respectively. Experimental results of the dual-mode filter which incorporates this resonator with parallel-coupled feed line with tuning stub at 5.8 GHz show good agreement with the simulated ones. The size for the resonator is only 4.7 × 3.4 mm (0.29λg×0.21λg in which λg is the guided wavelength of 50 Ω microstrip at 5.8 GHz).

1. Wang, Y. X., B.-Z. Wang, and J. P. Wang, "A compact square loop dual-mode bandpass filter with wide stop-band," Progress In Electromagnetics Research, Vol. 77, 67-73, 2007.
doi:10.2528/PIER07072707

2. Peng, Y. and W.-X. Zhang, "Microstrip band-reject filter based on inter-digital capacitance loaded loop resonator," Progress In Electromagnetics Research Letters, Vol. 8, 93-103, 2009.
doi:10.2528/PIERL09031501

3. Karthikeyan, S. S. and R. S. Kshetrimayum, "Harmonic suppression of parallel coupled microstrip line bandpass filter using CSRR," Progress In Electromagnetics Research Letters, Vol. 7, 193-201, 2009.
doi:10.2528/PIERL08122602

4. Chin, K.-S. and D.-J. Chen, "Novel microstrip bandpass filters using direct-coupled triangular stepped-impedance resonators for spurious suppression," Progress In Electromagnetics Research Letters, Vol. 12, 11-20, 2009.
doi:10.2528/PIERL09090602

5. Woff, I., "Microstrip bandpass filter using degenerate modes of a microstrip ring resonator," Electronics Letter, Vol. 8, No. 12, 13-15, 1972.

6. Kong, Y. W., X. D. Huang, C. H. Cheng, and S. T. Chew, "EBG-based dual mode resonator filter," IEEE Microwave and Wireless Components Lett., Vol. 14, No. 3, 124-126, 2004.
doi:10.1109/LMWC.2003.822570

7. Tan, B. T., J. J. Yu, S. T. Chew, M.-S. Leong, and B.-L. Ooi, "A miniaturized dual-mode ring bandpass filter with a new perturbation," IEEE Microwave and Wireless Components Lett., Vol. 53, No. 1, 343-345, 2005.

8. Huang, X. D. and C. H. Cheng, "A novel coplanar-waveguide bandpass filter using a dual-mode square-ring resonator," IEEE Microwave and Wireless Components Lett., Vol. 16, No. 1, 13-15, 2006.
doi:10.1109/LMWC.2005.861358

9. Kang, W., W. Hong, and J. Y. Zhou, "Performance improvement and size reduction of microstrip dual-mode bandpass filter," Electronics Letter, Vol. 44, No. 6, 421-422, 2008.
doi:10.1049/el:20080285

10. Hong, J.-S., H. Shaman, and Y.-H. Chun, "Dual-mode microstrip open-Loop resonators and filters," IEEE Trans. Microw. Theory Tech., Vol. 55, No. 8, 1764-1760, 2007.
doi:10.1109/TMTT.2007.901592

11. Athukorala, L. and D. Budimir, "Compact dual-mode open loop microstrip resonators and filters," IEEE Microwave and Wireless Components Lett., Vol. 19, No. 11, 670-698, 2007.

12. Rosenberg, U. and S. Amari, "Novel coupling schemes for microwave resonator filters," IEEE Trans. Microw. Theory Tech., Vol. 50, No. 12, 2896-2902, 2002.
doi:10.1109/TMTT.2002.805171

13. Liao, C.-K., P.-L. Chi, and C.-Y. Chang, "Microstrip realization of generalized chebyshev filters with box-like coupling schemes," IEEE Transactions on Microwave Theory and Techniques, Vol. 55, No. 1, 147-153, 2007.
doi:10.1109/TMTT.2006.888580

14. Wong, S. W. and L. Zhu, "Quadruple-mode UWB bandpass filter with improved out-of-band rejection," IEEE Microwave and Wireless Components Lett., Vol. 19, No. 3, 152-154, 2009.
doi:10.1109/LMWC.2009.2013735

15. Zhu, L., S. Sun, and W. Menzel, "Ultra-wideband (UWB) bandpass filters using multiple-mode resonator," IEEE Microwave and Wireless Components Lett., Vol. 15, No. 11, 796-798, 2005.
doi:10.1109/LMWC.2005.859011

Dr. Hong-Wei Deng

Dr. Yong-Jiu Zhao

Dr. Xue-Shun Zhang

Dr. Lu Zhang

Dr. Wei Zhao