A novel feeding network is investigated both theoretically and experimentally. The proposed system with combination of a Wilkinson power divider and two branch-Line couplers is established. The output signals of the system have the same amplitude and 900 phase difference with each other. The size reduction technique is applied to minimize the physical size of the proposed network. In this technique, the ground of the structure is defected, and distributed capacitors and inductors are added to empty space of the branch-line couplers. Moreover, meandered lines are used in order to match the output impedance of the Wilkinson power divider arms and reduce its size. The initial design realized in 2.5 GHz shows the fractional bandwidth of 24%. Then a miniaturized structure is fabricated with 42% smaller size than the main structure while it shows similar electrical performance. For both cases, measurement and simulation results are in good agreement with each other.
2. Maddio, S., "A compact wideband circularly polarized antenna array for C-band applications," IEEE Antennas and Wireless Propagation Letters, Vol. 14, 1081-1084, Dec. 2015.
doi:10.1109/LAWP.2015.2392387
3. Mohammadi, P. and V. Rafii, "High gain and broadband circularly polarized square slot antenna array," Progress In Electromagnetics Research Letters, Vol. 43, 105-113, 2013.
doi:10.2528/PIERL13080701
4. Chung, K. L., "High-performance circularly polarized antenna array using metamaterial-line based feed network," IEEE Transactions on Antennas and Propagation, Vol. 61, No. 12, 6233-6237, Dec. 2013.
doi:10.1109/TAP.2013.2282296
5. Pozar, D. M., Microwave Engineering, John Wiley & Sons Press, 2005.
6. Tang, C. W. and M. G. Chen, "Miniaturized microstrip branch-line couplers with the approach of p-model," Microw. Opt. Tech. Lett., Vol. 50, No. 2, 314-316, 2008.
doi:10.1002/mop.23061
7. Liao, S., P. T. Sun, N. C. Chin, and J. T. Peng, "A novel compact-size branch-line coupler," IEEE Microw. Wirel. Compon. Lett., Vol. 15, No. 9, 588-509, 2005.
doi:10.1109/LMWC.2005.855378
8. Tang, C. W., M. G. Chen, and C. H. Tsai, "Miniaturization of microstrip branch-line coupler with dual transmission lines," IEEE Microw. Wirel. Compon. Lett., Vol. 18, No. 3, 185-187, 2008.
doi:10.1109/LMWC.2008.916798
9. Liao, S. and J. T. Peng, "Compact planar microstrip branch-line couplers using the quasi-lumped elements approach with nonsymmetrical and symmetrical T-shaped structure," IEEE Trans. Microw. Theory Tech., Vol. 54, No. 9, 3508-3514, 2006.
doi:10.1109/TMTT.2006.880650
10. Wang, C. W., T. G. Ma, and C. F. Yang, "A new planar artificial transmission line and its applications to a miniaturized Butler matrix," IEEE Trans. Microw. Theory Tech., Vol. 55, No. 12, 2792-2801, 2007.
doi:10.1109/TMTT.2007.909474
11. Ghali, H. and T. A. Moselhy, "Miniaturized fractal rat-race, branch-line, and coupled-line hybrids," IEEE Trans. Microw. Theory Tech., Vol. 52, No. 11, 2513-2520, 2004.
doi:10.1109/TMTT.2004.837154
12. Eslamloo, M. K., P. Mohammadi, and M. Khoubrou, "Miniaturized wideband branch-line hybrid coupler with capacitive effect and defected ground structure (DGS)," Indian Journal of Science and Technology, Vol. 8, No. 35, December 2015.
doi:10.17485/ijst/2015/v8i35/71911
13. Esa, M., N. Philip, I. P. Pohan, and N. A. Murad, "Miniaturized microwave meander coupled-line two-way wilkinson power divider," International Symposium on Antennas and Propagation-ISAP, 2006.
14. Betancourt, D. and C. Del Ro, "Designing feeding networks with CORPS: Coherently radiating periodic structures," Microwave and Optical Technology Letters, Vol. 48, No. 8, August 2006.
doi:10.1002/mop.21697
15. Panduro, M. A., "Design of beam-forming Networks for Scannable multi-beam antenna arrays using CORPS," Progress In Electromagnetics Research, Vol. 84, 173-188, 2008.
doi:10.2528/PIER08070403
16. Fakoukakis, F. E. and G. A. Kyriacou, "Novel nolen matrix based beamforming networks for series-fed low SLL multibeam antennas," Progress In Electromagnetics Research B, Vol. 51, 33-64, 2013.
doi:10.2528/PIERB13011605
17. Gruszczyski, S., K. Wincza, and K. Sachse, "Reduced sidelobe four-beam N-element antenna arrays fed by 4N butler matrices," IEEE Antennas and Wireless Propagation Letters, Vol. 5, 2006.
Submit
