A compact interdigital capacitor coupled dual-behavior resonator (DBR) filter with high spurious responses suppression is proposed in this paper. The technique is based on two equivalent topologies of J-inverter and dual-line equivalent circuit of open-circuited stubs. The first compact equivalent topology capacitive inverter is a high pass structure, and consequently, the spurious responses can be suppressed effectively at low frequencies. The second equivalent topology π-network is employed in realizing a compact size and adding new transmission zeros dedicated to the spurious responses suppression at high frequencies. Further compactness is achieved with a dual-line equivalent circuit of open-circuited stubs. The relevant equations are given in the paper. Finally, a 3rd-order compact DBR filter is designed and measured. This structure has a high degree of miniaturization(83%) in comparison to the classical one. Measurement results show good agreement with the simulated ones.
2. Fan, J.-W., C.-H. Liang, and X.-W. Dai, "Design of cross-coupled dual-band filter with equal-length split-ring resonators," Progress In Electromagnetics Research, Vol. 75, 285-293, 2007.
3. Zhang, J., J.-Z. Gu, B. Cui, and X.-W. Sun, "Compact and harmonic suppression open-loop resonator bandpass filter with tri-section SIR," Progress In Electromagnetics Research, Vol. 69, 93-100, 2007.
4. Li, Z.-P., S.-J. Wang, T. Su, and C.-H. Liang, "A novel triple passband filter design method based on stepped impedance resonators," Progress In Electromagnetics Research C, Vol. 33, 199-211, 2012.
5. Quendo, C. and E. Rius, "Narrow bandpass filters using dual-behavior resonators," IEEE Trans. Microw. Theory Tech., Vol. 51, No. 3, 734-743, Mar. 2003.
6. Quendo, C. and E. Rius, "Narrow bandpass filters using dual-behavior resonators based on stepped-impedance stubs and different-length stubs," IEEE Trans. Microw. Theory Tech., Vol. 52, No. 3, 1034-1044, Mar. 2004.
7. Chen, C. H., H. Wu, and W. Wu, "High isolation DBR diplexer using in-line SCMRC," Progress In Electromagnetics Research C, Vol. 22, 97-108, 2011.
8. Koziel, S., S. Ogurtsov, and M. H. Bakr, "Variable-fidelity design optimization of microwave devices using multi-dimensional cauchy approximation and coarsely discretized electromagnetic models," Progress In Electromagnetics Research B, Vol. 21, 1-26, 2010.
9. Issa, H., et al., "Miniaturized DBR filter: Formulation and performances improvement," IEEE MTT-S International Microwave Symposium Digest, 671-674, Atlanta, USA, Jun. 2008.
10. Issa, H., J. M. Duchamp, S. Abou-Chahine, and P. Ferrari, "Compact semi-lumped two-pole DBR filter with spurious suppression," Asia-Pacific Microwave Conference Proceedings (APMC), 425-428, Dec. 2011.
11. Issa, H., et al., "Miniature DBR with series capacitive loading Microwave and Optical Technology Letters,", Vol. 53, No. 2, 278-281, Feb. 2011.
12. Manchec, A., C. Quendo, E. Rius, C. Person, and J. F. Favennec, "Synthesis of dual behavior resonator (DBR) filters with integrated low-pass structures for spurious response suppression," IEEE Microwave and Wireless Components Letters, Vol. 16, 4-6, Jan. 2006.
13. Ahn, C. S., Y. J. Sung, and Y. S. Kim, "Miniaturization and spurious suppression of dual-behavior resonator bandpass filter using compact microstrip resonant cell," Asia-Pacific Microwave Conference Proceedings (APMC), 1803-1806, New Delhi, India, Dec. 2004.
14. Rius, E., et al., "High rejection C-band planar band-pass filter for a spatial application," 33rd European Microwave Conference, Vol. 3, 1055-1058, Oct. 2003.
15. Manchec, A., C. Quendo, J. F. Favennec, E. Rius, and C. Person, "Synthesis of capacitive-coupled dual-behavior resonator (CCDBR) filters," IEEE Trans. Microw. Theory Tech., Vol. 54, No. 6, 2346-2355, Jun. 2006.
16. Manchec, A., et al., "Study of a C-band cross-coupled dual-behavior resonator filter with spurious responses suppression for a space application," 37th European Microwave Conference, 882-885, Oct. 2007.
17. Matthaei, G., L. Young, and E. M. T. Jones, Microwave Filters, Impedance-matching Networks, and Coupling Structures, 436-437, Artech House, Dedham, MA, 1980.
18. Mongia, R., I. Bahl, and P. Bhartia, RF and Microwave Coupled-line Circuits, 252-253, Artech House, Boston, London, 1999.
19. Zhu, L. and K. Wu, "Accurate circuit model of interdigital capacitor and its application to design of new quasi-lumped miniaturized filters with suppression of harmonic resonance," IEEE Trans. Microw. Theory Tech., Vol. 48, No. 3, 347-356, Mar. 2000.
20. Lin, C.-M., C.-C. Su, S.-H. Hung, and Y.-H. Wang, "A compact balun based on microstrip EBG cell and interdigital capacitor," Progress In Electromagnetics Research Letters, Vol. 12, 111-118, 2009.