In the paper, a compact wideband power divider (PD) which consists of a λ/4 unequal width three-coupled-lines, four short-circuited stubs and an airbridge resistor is presented. By connecting the four short-circuited stubs to the input and output ports of the PD, two additional transmission poles are obtained, which results in enhanced bandwidth and improved selectivity. Rigorous design equations are given according to the even-odd mode analysis, and the design parameters are obtained based on particle swarm optimization. For validation, a prototype operating at 1 GHz is fabricated and tested. The experimental results indicate that the proposed power divider exhibits a return loss of more than 17.5 dB and an isolation of larger than 18.8 dB isolation in the fractional bandwidth of 91%.
2. Cohn, S. B., "A class of broadband three-port TEM-mode hybrids," IEEE Trans. on Microwave Theory and Techniques, Vol. 16, No. 2, 110-116, Feb. 1968.
3. Bao, C., X. Wang, Z. Ma, C. P. Chen, and G. Lu, "An optimization algorithm in ultrawideband bandpass Wilkinson power divider for controllable equal-ripple level," IEEE Microwave and Wireless Components Letters, Vol. 30, No. 9, 861-864, Sep. 2020.
4. Ahmed, U. and A. Abbosh, "Compact power divider for wideband in-phase and out-of-phase performances using parallel coupled lines," Electronics Letters, Vol. 53, No. 19, 1312-1314, 2017.
5. Maktoomi, M. A., M. S. Hashmi, and F. M. Ghannouchi, "Theory and design of a novel wideband DC isolated Wilkinson power divider," IEEE Microwave and Wireless Components Letters, Vol. 26, No. 8, 586-588, Aug. 2016.
6. Yu, T., "A broadband Wilkinson power divider based on the segmented structure," IEEE Trans. on Microwave Theory and Techniques, Vol. 66, No. 4, 1902-1911, Apr. 2018.
7. Wong, S. W. and L. Zhu, "Ultra-wideband power divider with good in-band splitting and isolation performances," IEEE Microwave and Wireless Components Letters, Vol. 18, No. 8, 518-520, Aug. 2008.
8. Zhang, B. and Y. A. Liu, "Wideband filtering power divider with high selectivity," Electronics Letters, Vol. 51, No. 23, 1950-1952, Nov. 2015.
9. Liu, Y., L. Zhu, and S. Sun, "Proposal and design of a power divider with wideband power division and port-to-port isolation: A new topology," IEEE Trans. on Microwave Theory and Techniques, Vol. 68, No. 4, 1431-1438, Apr. 2020.
10. Chen, M. T. and C. W. Tang, "Design of the filtering power divider with a wide passband and stopband," IEEE Microwave and Wireless Components Letters, Vol. 28, No. 7, 570-572, Jul. 2018.
11. Jiao, L., Y. Wu, Y. Liu, Q. Xue, and Z. Ghassemlooy, "Wideband filtering power divider with embedded transversal signal-interference sections," IEEE Microwave and Wireless Components Letters, Vol. 27, No. 12, 1068-1070, Dec. 2017.
12. Guo, L., H. Zhu, and A. M. Abbosh, "Wideband tunable in-phase power divider using three-line coupled structure," IEEE Microwave and Wireless Components Letters, Vol. 26, No. 6, 404-406, Jun. 2016.
13. Dang, T. S., C. W. Kim, and S. W. Yoon, "Ultra-wideband power divider using three parallel-coupled lines and one shunt stub," Electronics Letters, Vol. 50, No. 2, 95-96, Jan. 2014.
14. Xu, K. D., Y. Bai, X. Ren, and Q. Xue, "Broadband filtering power dividers using simple three-line coupled structures," IEEE Trans. on Components, Packaging and Manufacturing Technology, Vol. 9, No. 6, 1103-1110, Jun. 2019.
15. Zhu, H., Z. Cheng, and Y. J. Guo, "Design of wideband in-phase and out-of-phase power dividers using microstrip-to-slotline transitions and slotline resonators," IEEE Trans. on Microwave Theory and Techniques, Vol. 67, No. 4, 1412-1424, Apr. 2019.
16. Song, K. and Q. Xue, "Novel ultra-wideband (UWB) multilayer slotline power divider with bandpass response," IEEE Microwave and Wireless Components Letters, Vol. 20, No. 1, 13-15, Jan. 2010.
17. Kong, M., Y. Wu, Z. Zhuang, W. Wang, and C. Wang, "Ultraminiaturized wideband Quasi- Chebyshev/-Elliptic impedance-transforming power divider based on integrated passive device technology," IEEE Trans. on Plasma Science, Vol. 48, No. 4, 858-866, Apr. 2020.
18. Liu, H., Y. Ma, M. Guan, S. Fang, and Z. Wang, "Synthesis of miniaturized wideband four-way filtering power divider consisting of unequal-width three-coupled-lines," Int. J. RF Microw. Comput. Aided Eng., Vol. 31, No. 10, e22805, Oct. 2021.
19. Muraguchi, M., T. Yukitake, and Y. Naito, "Optimum design of 3-dB branch-line couplers using microstrip lines," IEEE Trans. on Microwave Theory and Techniques, Vol. 31, No. 8, 674-678, Aug. 1983.