Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 31800
A New Microstrip Diplexer Using Coupled Stepped Impedance Resonators

Authors: A. Chinig, J. Zbitou, A. Errkik, L. Elabdellaoui, A. Tajmouati, A. Tribak, M. Latrach


This paper presents a new structure of microstrip band pass filter (BPF) based on coupled stepped impedance resonators. Each filter consists of two coupled stepped impedance resonators connected to microstrip feed lines. The coupled junction is utilized to connect the two BPFs to the antenna. This two band pass filters are designed and simulated to operate for the digital communication system (DCS) and Industrial Scientific and Medical (ISM) bands at 1.8 GHz and 2.45 GHz respectively. The proposed circuit presents good performances with an insertion loss lower than 2.3 dB and isolation between the two channels greater than 21 dB. The prototype of the optimized diplexer have been investigated numerically by using ADS Agilent and verified with CST microwave software.

Keywords: Band Pass Filter, coupled junction, coupled stepped impedance resonators, diplexer, insertion loss, isolation.

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 3035


[1] D. M. Pozar, Microwave Engineering, John Wiley & Sons 1998.
[2] E. Goron, J.P. Coupez, C. Person, Y. Toutain, H. Lattard, and F. Perrot, Accessing to UMTS filtering specifications using new microstrip miniaturized loop-filters, IEEE MTT-S Int Microwave Symp Dig Philadelphia, PA (2003), 1599–1602.
[3] Strassner, B. and K. Chang, “Wide-band low-loss high isolation microstrip periodic-stub diplexer for multiple-frequency applications”, IEEE Trans. Microw. Theory Tech., Vol. 49, 1818-1820, 2001.
[4] Ye, C. S., Y. K. Su, M. H. Weng, and C. Y. Hung, “A microstrip ringlike diplexer for bluetooth and ultra wide band (UWB) application, ” Microwave & Opt. Tech. Lett., Vol. 51, 1518-1520, 2009.
[5] Weng, M. H., C. Y. Hung, and Y. K. Su, “A hairpin line diplexer for direct sequence ultra-wideband wireless communications,” IEEE Microw. Wireless Compon. Lett., Vol. 17, 519-521, 2007.
[6] Chen, C. F., T. Y. Huang, C. P. Chou, and R. B. Wu, “Microstrip diplexers design with common resonator sections for compact size, but high isolation,” IEEE Trans. Microw. Theory Tech., Vol. 54, 1945-1952, 2006.
[7] F. Sheta, J. P. Coupez, G. Tanné, S. Toutain, and J. P. Bolt, “Miniature microstrip stepped impedance resonator band pass filters and diplexers for mobile communications,” 1996 IEEE MTT-S Digest, WE2C-2, pp. 607-610.
[8] W. W. Choi, and K. W. Tam, “A microstrip SIR dual-mode bandpass filter with simultaneous size reduction and spurious responses suppression, ” IEEE MTT-S International Microwave Workshop Series on Art of Miniaturizing RF and Microwave Passive Components, Chengdu, China, 2008.
[9] Tang, C. W. and H. H. Liang, “Parallel-coupled stacked SIRs bandpass filters with open-loop resonators for suppression of spurious responses,” IEEE Microw. Wireless Compon. Lett., Vol. 15, 802-804, 2005.
[10] Makimoto, M. and S. Yamashita, “Bandpass filters using parallelcoupled stripline stepped-impedance resonators,” IEEE Trans. Microw. Theory Tech., Vol. 28, 1413-1417, 1980.
[11] C. Quendo, E. Rius, C. Person, “ Narrow bandpass filters using dual behavior resonators (DBRs) based on stepped impedance stubs and differents-length stubs,” IEEE Trans. Microwave Theory & Tech, vol. 52, n°3, March 2004.
[12] Sugchai, Tantiviwat “A Design of Wide-Stopband Microstrip Diplexers with Multiorder Spurious-Mode Suppression Using Stepped-Impedance Resonators,” presented in IEEE Engineering and Technology (S-CET), 2012 Spring Congress, 27-30 May 2012.
[13] Puttadilok, Duangporn, “A microstrip diplexer filter using steppedimpedance resonators,” presented in IEEE SICE Annual Conference, 20-22 Aug 2008.
[14] S.-C. Lin, P.-H. Deng, Y.-S. Lin, C.-H. Wang and C. H. Chen, “Widestopband microstrip bandpass filters using dissimilar quarter-wavelength stepped-impedance resonators”, IEEE Trans. Microwave Theory Tech., Vol. 54, pp. 1011-1018, Mar. 2006.
[15] C.-W. Tang and H.-H. Liang, “Parallel-coupled stacked SIRs bandpass filters with open-loop resonators for suppression of spurious responses”, IEEE Microwave Wireless Comp. Lett., Vol. 15, pp. 802-804, Nov. 2005.
[16] H. Wang and L. Zhu, “Microstrip bandpass filters with ultra-broad rejection band using stepped impedance resonator and high-impedance transformer”, in IEEE MTT-S Int. Microwave Symp. Dig., pp. 683-686, Long Beach, USA, June 2005.