volume | PIER Journals

Abstract

In this paper, a planar microstrip branch-line coupler is designed to have dual-band operation. A Pi-typed structure is used in place of the conventional quarter wavelength transmission line for dual-band application. This structure consists of a pair of coupled line in which one has two ends while the other has open stubs attached to its two ends, and its circuit parameters are determined by the transmission line theory. Explicit design equations are derived using ABCD-matrix. For verification, a 3-dB branch line coupler with operating frequencies of 900 MHz and 3.5 GHz is fabricated and measured on an FR-4 printed circuit board (PCB). The simulated and measured results are in good agreement with each other.

1. Chang, S.-F., Y.-H. Jeng, and J.-L. Chen, "Dual-band step-impedance bandpass filter for multimode wireless LANs," Electronics Letters, Vol. 40, 38-39, 2004.
doi:10.1049/el:20040065 Google Scholar

2. Fan, J.-W., C.-H. Liang, and D. Li, "Design of cross-coupled dual-band filter with equal-length split-ring resonators," Progress In Electromagnetics Research, Vol. 75, 285-293, 2007.
doi:10.2528/PIER07060904 Google Scholar

3. Kamma, A., G. S. Reddy, R. S. Parmar, and J. Mukherjee, "Dual-band filter for WIMAX and WLAN with improved upper stop band performance," Progress In Electromagnetics Research C, Vol. 50, 131-138, 2014.
doi:10.2528/PIERC14042601 Google Scholar

4. Park, M.-J. and B. Lee, "Wilkinson power divider with extended ports for dual-band operation," Electronics Letters, Vol. 44, 916-917, 2008.
doi:10.1049/el:20080821 Google Scholar

5. Tang, X. and K. Mouthaan, "Compact dual-band power divider with single allpass coupled lines sections," Electronics Letters, Vol. 46, 688-689, 2010.
doi:10.1049/el.2010.3579 Google Scholar

6. Lin, F., Q.-X. Chu, and S. W. Wong, "Dual-band planar crossover with two-section branch-line structure," IEEE Transactions on Microwave Theory and Techniques, Vol. 61, 2309-2316, 2013.
doi:10.1109/TMTT.2013.2261084 Google Scholar

7. Shao, J., H. Ren, B. Arigong, C. Li, and H. Zhang, "A fully symmetrical crossover and its dual-frequency application," IEEE Transactions on Microwave Theory and Techniques, Vol. 60, 2410-2416, 2012.
doi:10.1109/TMTT.2012.2198229 Google Scholar

8. Lin, I-H., C. Caloz, and T. Itoh, "A branch-line coupler with two arbitrary operating frequencies using left-handed transmission lines," IEEE MTT-S International Microwave Symposium Digest, Vol. 1, 325-328, 2003. Google Scholar

9. Cheng, K.-K. M. and F.-L.Wong, "A novel approach to the design and implementation of dual-band compact planar 90◦ branch-line coupler," IEEE Transaction on Microwave Theory and Techniques, Vol. 52, 2458-2463, 2004.
doi:10.1109/TMTT.2004.837151 Google Scholar

10. Zhang, H. and K. J. Chen, "A stub tapped branch-line coupler for dual-band operations," IEEE Microwave and Wireless Components Letters, Vol. 17, 106-108, 2007.
doi:10.1109/LMWC.2006.890330 Google Scholar

11. Chin, K.-S., K.-M. Lin, Y.-H. Wei, T.-H. Tseng, and Y.-J. Yang, "Compact dual-band branch-line and rat-race couplers with stepped-impedance-stub lines," IEEE Transactions on Microwave Theory and Techniques, Vol. 58, 1213-1221, 2010.
doi:10.1109/TMTT.2010.2046064 Google Scholar

12. Zheng, N., L. Zhou, and W.-Y. Yin, "A novel dual-band Π-shaped branch-line coupler with steppedimpedanceA novel dual-band Π-shaped branch-line coupler with stepped-impedance stubs," Progress In Electromagnetics Research Letters, Vol. 25, 11-20, 2011.
doi:10.2528/PIERL11032915 Google Scholar

13. Wong, F.-L. and K.-K. M. Cheng, "A novel planar branch-line coupler design for dual-band applications," IEEE MTT-S International Microwave Symposium Digest, 903-906, 2004. Google Scholar

14. Park, M.-J. and B. Lee, "Dual-band, cross coupled branch line coupler," IEEE Microwave and Wireless Components Letters, Vol. 15, 655-657, 2005.
doi:10.1109/LMWC.2005.856683 Google Scholar

15. Kim, H., B. Lee, and M. Joo, "Dual-band branch-line coupler with port extensions," IEEE Transactions on Microwave Theory and Techniques, Vol. 58, 651-651, 2010.
doi:10.1109/TMTT.2010.2040342 Google Scholar

16. Atlasbaf, Z. and K. Forooraghi, "A new dual band branch-line coupler using coupled lines," ISAPE’06. 7th International Symposium on Antennas, Propagation & EM Theory, 1-4, 2006.
doi:10.1109/ISAPE.2006.353320 Google Scholar

17. Yeung, L. K., "A compact dual-band 90 coupler with coupled-line sections," IEEE Transactions on Microwave Theory and Techniques, Vol. 59, 2227-2232, 2232.
doi:10.1109/TMTT.2011.2160199 Google Scholar

18. Wang, X., W.-Y. Yin, and K.-L. Wu, "A dual-band coupled-line coupler with an arbitrary coupling coefficient," IEEE Transactions on Microwave Theory and Techniques, Vol. 60, 945-951, 2012.
doi:10.1109/TMTT.2012.2185949 Google Scholar

19. Katakam, S., H. Ren, J. Shao, M. Zhou, B. Arigong, J. Ding, and H. Zhang, "A dual-band branch line coupler based on pi-shaped coupled lines," Microwave and Optical Technology Letters, Vol. 57, 501-504, 2015.
doi:10.1002/mop.28879 Google Scholar

20. Collin, R. E., Foundations for Microwave Engineering, 2nd Ed., IEEE Press, 1992.

Dr. Yu Cao

Dr. Jincai Wen

Dr. Hui Hong

Dr. Jun Liu