volume | PIER Journals

Abstract

A new miniaturized microstrip branch-line coupler with good harmonic suppression is proposed in this paper. The new structure has two significant advantages, which not only effectively reduces the occupied area to 19.1% of the conventional branch-line coupler at 0.90 GHz, but also has high 7th harmonic suppression performance. The measured results indicate that a fractional bandwidth of more than 15.6% has been achieved while the phase difference between S₂₁ and S₃₁ is within 90° ± 0.8°. The measured fractional bandwidths of |S₂₁| and |S₃₁| within 3 ± 0.3 dB are 16.1% and 16.7%, respectively. Furthermore, the measured insertion loss is comparable to that of a conventional branch-line coupler. The new coupler can be easily implemented by using the standard printed-circuit-board etching processes and is very useful for wireless communication systems.

1. Pozar, D. M. Microwave Engineering, 3rd Ed., Ch. 7, 333-337, Wiley, New York, 2005.

2. Mohra, A., A. F. Sheta, and S. F. Mahmoud, "New compact 3 dB 0/180 microstrip coupler configurations," Applied Computational Electromagnetics Society (ACES) Journal, Vol. 19, No. 2, 108-112, 2004.

3. Xiao, B., J. Hong, and B. Wang, "A novel UWB out-of-phase four-way power divider," Applied Computational Electromagnetics Society (ACES) Journal, Vol. 26, No. 10, 863-867, 2011.

4. Shamaileh, K. A., A. Qaroot, N. Dib, and A. Sheta, "Design of miniaturized unequal split Wilkinson power divider with harmonics suppression using non-uniform transmission lines," Applied Computational Electromagnetics Society Journal, Vol. 26, No. 6, 530-538, 2011.

5. Eccleston, K. W. and S. H. M. Ong, "Compact planar microstripline branch-line and rat-race couplers," IEEE Transactions on Microwave Theory and Techniques, Vol. 51, No. 10, 2119-2125, 2003.
doi:10.1109/TMTT.2003.817442

6. Mondal, P. and A. Chakrabarty, "Design of miniaturized branch-line and rat-race hybrid couplers with harmonics suppression," IET Microw. Antennas Propag., Vol. 3, No. 1, 109-116, 2009.
doi:10.1049/iet-map:20070202

7. Gu, J. and X. Sun, "Miniaturization and harmonic suppression of branch-line and rat-race hybrid coupler using compensating spiral compact micostrip resonant cell," IEEE MTT-S Int. Dig., 1211-1214, 2005.

8. Wang, J., B.-Z. Wang, Y. X. Guo, L. C. Ong, and S. Xiao, "A compact slow-wave microstrip branch-line coupler with high performance," IEEE Microwave and Wireless Components Letters, Vol. 17, No. 7, 501-503, 2007.
doi:10.1109/LMWC.2007.899307

9. Velidi, V. K., B. Patel, and S. Sanval, "Harmonic suppressed compact wideband branch-line coupler using unequal length open-stub units," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 21, No. 1, 115-119, 2011.
doi:10.1002/mmce.20495

10. Tsai, K. Y., H. S. Yang, J. H. Chen, and Y. J. Chen, "A miniaturized 3 dB branch-line hybrid coupler with harmonics suppression," IEEE Microwave and Wireless Components Letters, Vol. 21, No. 10, 537-539, 2011.
doi:10.1109/LMWC.2011.2164901

11. Velidi, V. K., A. Pal, and S. Sanyal, "Harmonics and size reduced microstrip branch-line baluns using shunt open-stubs," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 21, No. 2, 115-119, 2011.
doi:10.1002/mmce.20495

12. Yang, X., Z. Liao, and X.-C. Zhang, "Design of miniaturized rat-race couplers with arbitrary power division ratios," Progress In Electromagnetics Research Letters, Vol. 741, 83-89, 2018.
doi:10.2528/PIERL17110805

13. Sun, K. O., S. J. Ho, C. C. Yen, and D. Weide, "A compact branch-line coupler using discontinuous microstrip lines," IEEE Microwave and Wireless Components Letters, Vol. 15, 519-520, 2005.
doi:10.1109/LMWC.2005.852789

14. Nosrati, M., "An extremely miniaturized microstrip branch-line coupler," Micro. and Optical Technology Letters, Vol. 51, 1403-1406, 2008.

15. Cheng, K. M. and F. L. Wong, "A novel approach to the design and implementation of dual-band compact planar 90^{o^{branch-line coupler," IEEE Transactions on Microwave Theory and Techniques, Vol. 52, 2458-2463, 2004.
doi:10.1109/TMTT.2004.837151}}

16. Zhang, H. L. 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

17. Nosrati, M., M. Daneshmand, and B. S. Virdee, "Novel compact dual-narrow-wideband branchline couplers using T-SHAPED stepped-impedance-stub lines," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 21, 642-649, 2011.
doi:10.1002/mmce.20559

Dr. Hai Zhang

Mr. Xiaolu Lu