Progress In Electromagnetics Research
ISSN: 1070-4698, E-ISSN: 1559-8985
Home | Search | Notification | Authors | Submission | PIERS Home | EM Academy
Home > Vol. 115 > pp. 423-439


By J. Shi, J.-X. Chen, and Z.-H. Bao

Full Article PDF (719 KB)

In this paper, microstrip line resonators with loaded elements are proposed and studied to design microstrip diplexer. To demonstrate the design ideas, the equivalent circuits of the proposed resonators are built and studied. It is found that the different loads on different positions of the proposed half-wavelength resonator make the resonator have different features, which will easily control the characteristic of the diplexers. And here, resistor, open stub, and shorted stub are used as loaded elements. It is found the resistor loaded on the center of the microstrip line resonator can extremely reduce the unloaded quality factor of even-mode resonant frequency, which can be used to suppress the harmonics of the diplexer. The loaded open stub not only can reduce the size of the diplexer, but also can control the frequency ratio between the fundamental frequency and second harmonic of a resonator, which can increases the frequency ratio between the two passbands of the diplexer. As for the loaded shorted stub, it can enlarge the size of the diplexer. To demonstrate the design ideas, three diplexers are presented. The comparisons between the loaded and unloaded diplexers are given. The experimental results agree well to the theoretical predictions and simulations.

J. Shi, 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.

1. Pozar, D. M., Microwave Engineering, 2nd Ed., Vol. 8, Wiley, New York, 1998.

2. Oh, S. S. and Y. S. Kim, "A compact duplexer for IMT-2000 handsets using microstrip slow-wave open-loop resonators with high-impedance meander lines," Radio Wireless Conf., 177-180, Aug. 2001.

3. Goron, E., 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. Microw. Symp. Dig., 1599-1602, Jun. 2003.

4. Konpang, J., A compact diplexer using square open loop with stepped impedance resonators, Asia-Pacific Microwave Conference, 1-4, 2008.

5. Srisathit, S., S. Patisang, R. Phromloungsri, S. Bunnjaweht, S. Kosulvit, and M. Chongcheawchamnan, "High isolation and compact size microstrip hairpin diplexer," IEEE Microw. Wireless Compon. Lett., Vol. 15, No. 2, 101-103, Feb. 2005.

6. Cabral, H. A., A diplexer for UMTS applications, IEEE MTT-S International Microwave and Optoelectronics Conference, 215-217, 2009.

7. Li, K.-H., C.-W. Wang, and C.-F. Yang, A miniaturized diplexer using planar artificial transmission lines for GSM/DCS applications, Asia-Pacific Microwave Conference, 1-4, 2007.

8. Yatsenko, A., D. Orlenko, S. Sakhnenko, G. Sevskiy, and P. Heide, "A small-size high-rejection LTCC diplexer for WLAN applications based on a new dual-band bandpass filter," IEEE MTT-S Int. Microw. Symp. Dig., 2113-2116, 2007.

9. Deng, P.-H., C.-H. Wang, and C. H. Chen, Compact microstrip diplexers based on a dual-passband filter, Asia-Pacific Microwave Conference, 1228-1232, 2006.

10. Xue, Q. and J.-X. Chen, "Compact diplexer based on double-sided parallel-strip line," Electronics Letters, Vol. 44, No. 2, 123-124, Jan. 2008.

11. Tsai, C. M., S. Y. Lee, C. C. Chuang, and C. C. Tsai, "A folded coupled-line structure and its application to filter and diplexer design," IEEE MTT-S Int. Microw. Symp. Dig., 1927-1930, Jun. 2002.

12. Xu, W.-Q., M.-H. Ho, and C. G. Hsu, "UMTS diplexer design using dual-mode stripline ring resonators," Electronics Letters, Vol. 43, No. 13, 721-722, Jun. 2007.

13. 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.

14. Chen, C.-F., T.-Y. Huang, C.-P. Chou, and R.-B.Wu, "Microstrip diplexers design with common resonator section for compact size, but high isolation," IEEE Trans. Microw. Theory Tech., Vol. 54, No. 5, 1945-1952, May 2006.

15. 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.

16. He, Z. R., X. Q. Lin, and Y. Fan, "Improved stepped-impedance resonator (SIR) bandpass filter on Ka-band," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 8--9, 1181-1190, 2009.

17. Yang, M. H., J. Xu, Q. Zhao, and X. Sun, "Wide stopband and miniarurized lowpass filters using SIRs-loaded hairpin resonators," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 17--18, 2385-2396, 2009.

18. 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.

19. 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.

20. Gu, 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.

21. 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.

22. Zhang, X. Y. and Q. Xue, "Novel centrally loaded resonators and their applications to bandpass filters," IEEE Trans. Microw. Theory Tech., Vol. 56, 913-921, Apr. 2008.

23. Hong, J.-S. and M. J. Lancaster, Microstrip Filter for RF/Microwave Applications, Wiley, New York, 2001.

© Copyright 2014 EMW Publishing. All Rights Reserved