To reduce the size and improve the performance, a 4th-order miniaturized dual-mode microstrip bandpass filter (BPF) is developed. A meander shorted stub loaded resonator is used, and much compact size is obtained. Theoretical model is set up, and the odd and even modes of the BPF are analyzed based on a symmetrical structure. Full wave simulation validates the design method. To verify the design, a fabricated BPF sample has been tested. Experiment result demonstrates that the designed BPF has wider stopband and better selectivity. Its fractional bandwidth and a center frequency are available.
2. Wolff, I., "Microstrip bandpass filter using degenerate modes of a microstrip ring resonator," Electron. Lett., Vol. 8, No. 12, 302-303, Jun. 1972.
3. Kuo, J.-T., C.-Y. Fan, and S.-C. Tang, "Dual-wideband bandpass filters with extended stopband based on coupled-line and coupled three-line resonators," Progress In Electromagnetics Research, Vol. 124, 1-15, 2012.
4. Tan, B.-T., S.-T. Chew, M.-S. Leong, and B.-L. Ooi, "A modified microstrip circular patch resonator filter," IEEE Microw. Wirel. Compon. Lett., Vol. 12, 252-254, Jul. 2002.
5. Chaudhary, G., Y. Jeong, K. Kim, and D. Ahn, "Design of dual-band bandpass filters with controllable bandwidths using new mapping function," Progress In Electromagnetics Research, Vol. 124, 17-34, 2012.
6. Hsieh, L.-H. and K. Chang, "Compact size and low insertion loss chebyshev-function bandpass filters using dual-mode patch resonators," Electron. Lett., Vol. 37, No. 17, 1070-1071, Aug. 2001.
7. Hong, J.-S. and M. J. Lancaster, "Bandpass characteristics of new dualmode microstrip square loop resonators," Electron. Lett., Vol. 31, No. 11, 91-892, Nov. 1995.
8. Hong, J. S. and M. J. Lancaster, "Microstrip bandpass filter using degenerate modes of a novel meander loop resonator," IEEE Microwave and Guided Wave Lett., Vol. 5, No. 11, 371-372, Nov. 1995.
9. Hong, J.-S., H. Shaman, and Y.-H. Chun, "Dual-mode microstrip openloop resonators and filters," IEEE Trans. Microw. Theory Tech., Vol. 55, No. 8, 1764-1770, Aug. 2007.
10. Zhou, M.-Q., X.-H. Tang, and F. Xiao, "Compact dual band bandpass filter using novel e-type resonators with controllable bandwidths," IEEE Microw. Wirel. Compon. Lett., Vol. 18, No. 12, 779-781, Dec. 2008.
11. Chen, F.-C., Q.-X. Chu, and Z.-H. Tu, "Design of compact dual-band bandpass filter using short stub loaded resonator," Microw. Opt. Technol. Lett., Vol. 51, No. 4, 959-963, Apr. 2009.
12. Ansoft Corporation, HFSS User's Guide, Version 10, 2005.