Design Formulas for Broadband Concentric Circular-Loops Antennas

Main Article Content

S. M. Ali Hamed
A. A. Osman


This paper presents a simple formulas for designing broadband concentric circular-loops antennas (CCLAs). The loop dimensions for widest bandwidth are expressented in terms of the resonance frequency of the driven loop. The analysis addresses both cases CCLAs with and without ground planes. The presented formulas are employed to design multiple CCLAs.  For example, a 3-elements CCLA of a maximum radius of 6.34 cm can be designed to operate with a voltage standing wave ratio (VSWR) < 2 over a frequencies band of a fractional bandwidth of 16.9% with a minimum directivity of 3.9 dB. Addionationally, a 4-elements CCLA of maximum radius of 15 cm can be design to operate in the frequency band extending from 825 MHz to 991 MHz (fractional bandwidth of 18.3%) with a VSWR < 2 and directivity higher than 5.2 dB over the entire band. Furthermore, the analysis shows that a 3-elements CCLA backed with a conducting ground plane improves the fractional bandwidth to 19.6% and directivity to 9.15 dB over the band of interest. The analytical results on designed antennas are validated with simulation results obtained by using the AN-SOF antenna simulation software. An excellent agreement is observed between analytical and AN-SOF simulations results.


Download data is not yet available.

Article Details

How to Cite
Ali Hamed, S., & Osman, A. (2015). Design Formulas for Broadband Concentric Circular-Loops Antennas. Advanced Electromagnetics, 4(1), 45-51.
Research Articles


  1. G. S. Smith, "loop antennas," in Antenna Engineering Handbook, R. C. Johnson and H. Jasik, Eds. New York: McGraw-Hill, ch. 5, 2007.

  2. S. Ito, N. Inagaki, and T. Sekiguchi, Investigation of the array of circular-loop antennas, IEEE Trans. Antennas Propagat. 4: 469-476, 1971.
    View Article

  3. R. W. P. King, The loop antenna for transmission and reception, In Antenna Theory, Part I, Collin, R. E. and Zucker, F. J. New York: McGraw-Hill, 1969.

  4. R. W. P. King and G. S. Smith, Antenna in Matter: Fundamentals, Theory and Applications, Cambridge, MA: MIT press, pp. 527-569, 1981.

  5. C. A. Balanis, Antenna Theory, Analysis, and Design, New York: Harper and Row, ch. 5, 1982. [6] A. Shoamanesh, and L. Shafei, Characteristics of circular loop antenna above a lossless ground plane, IEEE Trans. Antennas Propagat. AP-29: 528-529, 1981.

  6. H. A. N. Hejase, S. D. Gedney, and K. W. White, Effect of a finite ground plane on radiated emission of a circular loop antenna, IEEE Trans. Electromagn. Compat. EMC-36: 364-371, 1994.
    View Article

  7. B. S. Hoon, L. Byungje, and J. H. Frances, Multi-band internal loop antenna with inserted concentric rings for mobile terminals, in Proc., IEEE Antennas and Propagat. Int. Symposium, pp. 4725-4728, 2007.

  8. R. L. Li, G. DeJean, J. Laskar, and M. M. Tentzeris Investigation of circularly polarized loop antennas with parasitic element for bandwidth enhancement, IEEE Trans. Antennas Propagat. AP-53: 3930-3939, 2005.

  9. H. Nakano, M. Fukasawa, and J. Yamauchi, Discrete multiloop, modified multiloop, and plate-loop antennas-multifrequency and wide-band VSWR characteristics, IEEE Trans. Antennas Propagat. AP-50: 371-378, 2002.
    View Article

  10. S. M. A. Hamed and M. A. H. Abbas, Radiation from a circular loop antenna placed coaxially relative to a conducting body of revolution, IEEE Trans. Antennas Propagat. AP-60: 4937- 4940, 2012.
    View Article

  11. S. M. A. Hamed and S. O. Bashir, Characteristics of a circular loop in the presence of a coaxial conducting BOR attached to a planar Reflector, IEEE Antennas and Wireless Propagat. Letters 12: 793 - 796, 2013.
    View Article

  12. A. C. Schell and E. L. Bouche, A concentric loop array, in Proc. WESCON, pp. 212-218, 1958.
    View Article

  13. Z. N. Chen, X. Qing and H. L. Chung, A universal UHF RFID reader antenna, IEEE Trans. Microwave Theory and Techniques 57: 1275- 1282, 2009.
    View Article

  14. X. Qing, C. K. Goh and Z. N. Chen, A broadband UHF near-field RFID antenna, IEEE Trans. Antennas Propagat. AP-58: 3829- 3838, 2010.
    View Article

  15. X. Li and J. Liao, Eye-shaped segmented reader antenna for near-field UHF RFID applications, Progress In Electromagnetics Research 114: 481- 493, 2011.
    View Article

  16. S. Fan, S. Zheng, Y. Cai, Y. Yin, Y. Hu, and J. Yang, Design of a novel wideband loop antenna with parasitic resonators, Progress In Electromagnetics Research Letters 37: 47- 54, 2013.
    View Article

  17. Y. Li, Z. Xie and X. Cen, Compact loop antenna for near-field and far-field UHF RFID applications, Progress In Electromagnetics Research C 37: 171- 182, 2013.
    View Article

  18. P. Wang, G. Wen, J. Li, Y. Huang, L. Yang and Q. Zhang, Wideband circularly polarized UHF RFID reader antenna with high gain and wide axial ratio beamwidths, Progress In Electromagnetics Research 129: 365- 385, 2012.
    View Article

  19. X. Lai, J. Ouyang and P. Yang, A circularly polarized compact antenna for UHF band RFID reader, Progress In Electromagnetics Research Letters 42: 119- 127, 2013.
    View Article

  20. J. Uddin, M. B. I. Reaz, M. A. Hasan, N. A. Nordin, M. I. Ibrahimy and M. A. M. Ali, UHF RFID antenna architectures and applications, Scientific Research and Essays 5(10): 1033- 1051, 2010.