A novel compact quadruplexer based on defected stepped impedance resonator (DSIR) with high isolation is presented in this paper. The proposed quadruplexer consists of a common input feeding line, four kinds of folded DSIRs and four individual output feeding lines. Considering the loading effect among channel filters, the input DSIRs must be properly located with respect to the common feeding line in order to realize all external quality factors at the same time, so that the loading effect becomes very small. Furthermore, since the compact DSIRs resonate at multiple fundamental frequencies, a high-isolation quadruplexer with size reduction can be obtained. A fabricated prototype of the proposed quadruplexer is developed. The channel performance obtained by measurement and EM simulation are in good agreement.
2. Jimenez Martin, J. L., V. Gonzalez-Posadas, J. E. GonzalezGarcia, F. J. Arques-Orobon, L. E. Garcia-Munoz, and D. Segovia-Vargas, "Dual band high efficiency class ce power amplifier based on CRLH diplexer," Progress In Electromagnetics Research, Vol. 97, 217-240, 2009.
3. Zewani, M. and I. C. Hunter, "Design of ring-manifold microwave multiplexers," IEEE MTT-S Int. Dig., 689-692, San Francisco, CA, Jun. 2006.
4. Deng, P.-H., N.-I. Lai, S.-K. Jeng, and C. H. Chen, "Design of matching circuits for microstrip triplexers based on stepped-impedance resonators," IEEE Trans. Microwave Theory Tech., Vol. 54, 4185-4192, 2006.
5. Shi, J., J.-X. Chen, and Z.-H. Bao, "Diplexers based on microstrip line resonators with loaded elements," Progress In Electromagnetics Research, Vol. 115, 423-439, 2011.
6. Yao, W. H., A. E. Abdelmonem, J. F. Liang, X. P. Liang, K. A. Zaki, and A. Martin, "Wide-band waveguide and ridge waveguide T-junctions for diplexer applications," IEEE Trans. Microwave Theory Tech., Vol. 41, 2166-2173, 1993.
7. Han, S., X.-L. Wang, Y. Fan, Z. Yang, and Z. He, "The generalized Chebyshev substrate integrated waveguide diplexer," Progress In Electromagnetics Research, Vol. 73, 29-38, 2007.
8. Chen, X.-W., W.-M. Zhang, and C.-H. Yao, "Design of microstrip diplexer with wide band-stop," International Conference on Microwave and Millimeter Wave Technology, 1-3, 2007.
9. Yang, R.-Y., C.-M. Hsiung, C.-Y. Hung, and C.-C. Lin, "Design of a high band isolation diplexer for GPS and WLAN system using modi¯ed Stepped-Impedance Resonators," Progress In Electromagnetics Research, Vol. 107, 101-114, 2010.
10. He, Z. R., X. Q. Lin, and Y. Fan, "Improved stepped-impedance resonator (SIR) bandpass filter in Ka-band," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 8-9, 1181-1190, 2009.
11. Yang, M. H., J. Xu, Q. Zhao, and X. Sun, "Wide-stopband and miniaturized lowpass filters using SIRs-loaded hairpin resonators," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 17-18, 2385-2396, 2009.
12. Yang, R.-Y., C.-M. Hsiung, C.-Y. Hung, and C.-C. Lin, "A high performance bandpass filter with a wide and deep stopband by using square stepped impedance resonators," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 11-12, 1673-1683, 2010.
13. Yu, W.-H., J.-C. Mou, X. Li, and X. Lv, "A compact filter with sharp-transition and wideband-rejection using the novel defected ground structure ," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 2-3, 329-340, 2009.
14. Guo, Y. C., L. H. Weng, and X. W. Shi, "An improved microstrip open loop resonator bandpass filter with DGSS for WLAN application," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 4, 463-472, 2009.
15. Huang, C.-Y., M.-H. Weng, C.-S. Ye, and Y.-X. Xu, "A high band isolation and wide stopband diplexer using dual-mode stepped-impedance resonators," Progress In Electromagnetics Research, Vol. 100, 299-308, 2010.
16. Deng, P. H., C. H. Wang, and C. H. Chen, Compact microstrip diplexers based on a dual-passband filter, Proceedings of Asia-Pacific Microwave Conference, 2006.
17. Wu, H.-W., K. Shu, M.-H. Weng, J.-R. Chen, and Y.-K. Su, Design of a compact microstrip triplexer for multiband applications, Proc. Eur. Microw. Conf., 834-837, 2007.
18. Chen, C.-F., T.-Y. Huang, T.-M. Shen, and R.-B. Wu, "A miniaturized microstrip common resonator triplexer without extra matching network," Proc. Asia-Paci¯c Microw. Conf., 1439-1442, 2006.
19. Chen, C.-F., T.-Y. Huang, C.-P. Chou, and R.-B.Wu, "Microstrip diplexer design with common resonator section for compact size but high isolation," IEEE Trans. Microwave Theory Tech., Vol. 54, 1945-1952, 2006.
20. Amari, S., "Synthesis of cross-coupled resonator filters using an analytical gradiant-based optimization technique," IEEE Trans. Microwave Theory Tech., Vol. 9, 1559-1564, 2000.
21. Huang, J.-Q., Q.-X. Chu, and C.-Y. Liu, "Compact UWB filter based on surface-coupled structure with dual notched bands," Progress In Electromagnetics Research, Vol. 106, 311-319, 2010.
22. Wei, F., L. Chen, Q.-Y. Wu, X.-W. Shi, and C.-J. Gao, "Compact UWB bandpass filter with narrow notch-band and wide stop-band," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 7, 911-920, 2010.
23. Hsiao, P.-Y. and R.-M. Weng, "Compact open-loop UWB filter with notched band," Progress In Electromagnetics Research Letters, Vol. 7, 149-159, 2009.
24. Hong, J.-S. and M. J. Lancaster, Microstrip Filter for F/Microwave Applications, Wiley, New York, 2001.