A dual-mode dual-band bandpass microstrip filter using double square-loop structure is proposed in this paper. Each of the square-loop forms a dual-mode resonator with controllable respective passband. Two tuning patches placed symmetrically at the side of the perturbation patch are used to change the higher passband frequency, while while keeping the lower invariable. Several attenuation poles in the stopband are realized to improve the selectivity of the proposed bandpass filter. The filter is evaluated by experiment and simulation with good agreement.
1. Levy, R., "Zolotarev functions,a new distribution prototype filter, and the design of mixed lumped/distributed components," IEEE G-MTT Microwave Int. Symp. Dig., Vol. 70, 71-75, 1970. doi:10.1109/GMTT.1970.1122772
2. Wang, J., Y.-X. Guo, B.-Z. Wang, L. C. Ong, and S. Xiao, "High-selectivity dual-band stepped-impedance bandpass filter," Electronics Letters, Vol. 42, No. 9, 538-540, 2006. doi:10.1049/el:20064491
3. Sun, S. and L. Zhu, "No vel design of dual-band microstrip bandpass filters with good in-between isolation," IEEE APMC 2005, 2005.
4. Tsai, L.-C. and C.-W. Hsue, "Dual-band bandpass filters using equallength coupled-serial-shunted lines and z-transform techniques," IEEE Trans. Microw. Theory Tech., Vol. 52, No. 4, 1111-1117, 2004. doi:10.1109/TMTT.2004.825680
5. Tu, W.-H. and K. Chang, "Miniaturized dual-mode bandpass filter with harmonic control," IEEE Microwave and Wireless Components Letters, Vol. 15, No. 12, 2005.
6. Hong, J.-S. and M. J. Lancaster, Microstrip triangular patch resonator filters, IEEE MTT-S International Microwave Symposium Digest, Vol. 1, No. 6, 331-334, 2000.
7. Görur, A., "Description of coupling between degenerate modes of a dual-mode microstrip loop resonator using a novel perturbation arrangement and its dual-mode bandpass filter applications," IEEE Trans. Microw. Theory Tech., Vol. 52, No. 2, 671-677, 2004. doi:10.1109/TMTT.2003.822033
8. Hong, J. S. and M. J. Lancaster, "Realization of quasielliptic function filter using dual-mode microstrip square loop resonators," Electron. Lett., Vol. 31, 2085-2086, 1995. doi:10.1049/el:19951433
9. Hseih, L.-H. and K. Chang, "Compact dual-mode elliptic-function bandpass filter using a single ring resonator with one coupling gap," Electron. Lett., Vol. 36, No. 9, 1626-1627, 2000. doi:10.1049/el:20001172
10. Chen, J.-X. and T. Y. Yum, "Dual-mo de dual-band bandpass filter using stacked-loop structure," IEEE Microwave and Wireless Components Letters, Vol. 16, No. 9, 2006. doi:10.1109/LMWC.2006.880705
11. Stewart, J. W. and M. J. Havrilla, "Electromagnetic characterization of a magnetic material using an open-ended waveguide probe and a rigorous full-wave multimode model," J. of Electrom. Waves and Appl., Vol. 20, No. 14, 2037-2052, 2006. doi:10.1163/156939306779322693
12. Xiao, J.-K., S.-P . Li, and Y. Li, "No vel planar bandpass filters using one single patch resonators with corner cuts," J. of Electrom. Waves and Appl., Vol. 20, No. 11, 1481-1493, 2006. doi:10.1163/156939306779274327
13. Xiao, J.-K. and Y. Li, "No vel compact microstrip square ring bandpass filters," J. of Electrom. Waves and Appl., Vol. 20, No. 13, 1817-1826, 2006. doi:10.1163/156939306779292156
14. Kazerooni, M. and A. Cheldavi, "Sim ulation,analysis,design and applications of array defected microstrip structure (ADMS) filters using rigorously coupled multi-strip (RCMS) method," Progress In Electromagnetics Research, Vol. 63, 193-207, 2006. doi:10.2528/PIER06052803
15. Khalaj-Amirhosseini, M., "Micr owave filters using waveguides filled by multi-layer dielectric," Progress In Electromagnetics Research, Vol. 66, 105-110, 2006. doi:10.2528/PIER06102502