volume | PIER Journals

Abstract

A new microstrip diplexer with very high output isolation and low insertion losses is presented in this letter. With the adoption of the spiral compact microstrip resonant cell (SCMRC) form into the dual behavior resonator (DBR) microstrip filter design, a bandpass filter with high rejection in the upper stopband can be achieved. Therefore, very high output isolation for the diplexer can be realized. Furthermore, the proposed diplexer also has a property of low insertion loss in the passband. To validate the design theory, one demonstrator diplexer has been designed and fabricated; the results indicate that the proposed diplexer has good performance of simple structure, better than 65 dB output isolation in the stopband, and less than 1.2 dB insertion losses in the passband.

1. Zhang, A., D. He, and Q. Yin, "Design of diplexer based on microstrip tapped-hairpin filter with frequency in S-band," Modern Electronics Technique, Vol. 19, 11-13, 2007.

2. 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.
doi:10.2528/PIER09112701

3. 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 modified stepped-impedance resonators," Progress In Electromagnetics Research, Vol. 107, 101-114, 2010.
doi:10.2528/PIER10060913

4. Sarayut, S., P. Sumongkol, P. Ravee, B. Sawat, K. Sompol, and C. Mitchal, "High isolation and compact size microstrip hairpin diplexer," Microw. Wirel. Comp. Lett., Vol. 15, No. 2, 101-103, 2005.
doi:10.1109/LMWC.2004.842839

5. Chen, Y. C., H. F. Cheng, C. M. Lei, and I. N. Lin, "Chebyshev-type diplexers designed using coupling matrix method," Mater. Chem. Phys., Vol. 79, No. 2-3, 116-118, 2003.
doi:10.1016/S0254-0584(02)00250-X

6. 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.
doi:10.2528/PIER07032002

7. Yang, T., P. L. Chi, and T. Itoh, "High isolation and compact diplexer using the hybrid resonators," Microwave Wirel. Comp. Lett., Vol. 20, No. 10, 551-553, 2010.
doi:10.1109/LMWC.2010.2052793

8. Manchec, A., R. Bairavasubramanian, C. Quendo, S. Pinel, E. Rius, C. Person, J. F. Favennec, J. Papapolymerou, and J. Laskar, "High rejection planar diplexer on liquid crystal polymer substrates using oversizing techniques," Microwave Conference, European, Vol. 1, 2005.

9. Manchec, A., E. Rius, C. Quendo, C. Person, J. F. Favennec, P. Moroni, J. C. Cayrou, and J. L. Cazaux, "Ku-band microstrip diplexer based on dual behavior resonator filter," Microwave Symposium Digest, IEEE MTT-S International, 525-528, 2005.

10. Singh, K., K. Ngachenchaiah, D. Bhatnagar, and S. Pal, "Notch implemented dual behavior resonator filter and diplexer at Ku-band," Microwave Journal, Euro-Global Edition, Vol. 53, 206-216, 2010.

11. Quendo, C., E. Rius, and C. Person, "Narrow bandpass filters using dual-behavior resonators," IEEE Trans. Microw. Theory Tech., Vol. 51, No. 3, 734-743, 2003.
doi:10.1109/TMTT.2003.808729

12. Quendo, C., E. Rius, and C. Person, "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, 2004.
doi:10.1109/TMTT.2004.823582

13. Xue, Q., K. M. Shum, and C. H. Chan, "Novel 1-D microstrip PBG cells," IEEE Microwave Guided Wave Lett., Vol. 10, 403-405, 2000.

14. Yum, T. Y., Q. Xue, and C. H. Chan, "Novel subharmonically pumped mixer incorporating dual-band stub and in-line SCMRC," IEEE Trans. Microw. Theory Tech., Vol. 51, 2538-2547, 2003.

Dr. Chunhong Chen

Dr. Hongmei Wu

Dr. Wen Wu