volume | PIER Journals

Abstract

This paper proposes an improved mathematical formulation of Johnston's approach to measure the radiation efficiency of an antenna, based on the Wheeler Cap (WC) technique. The proposed modifications allow the measurement of the radiation efficiency of small antennas matched to complex loads implemented on Radio Frequency IDentification (RFID) tags. The studied structure is a low-cost, silver-printed, differentially-fed RFID dipole antenna. The antenna is printed on a flexible PET (polyethylene terephthalate) paper that is conformable on various objects. Link budget measurements validate the accuracy of the formulation, which can be applied to any dipole antenna matched to an RFID chip with a complex input impedance.

1. Sharif, A., J. Ouyang, Y. Yan, A. Raza, M. A. Imran, and Q. H. Abbasi, "Low-cost inkjet-printed RFID tag antenna design for remote healthcare applications," IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology, Vol. 3, No. 4, 261-268, Dec. 2019.
doi:10.1109/JERM.2019.2924823

2. Turalchuk, P., I. Munina, M. Derkach, O. Vendik, and I. Vendik, "Electrically small loop antennas for RFID applications," IEEE Antennas and Wireless Propagation Letters, Vol. 14, 1786-1789, 2015.
doi:10.1109/LAWP.2015.2423854

3. Mobashsher, A. T., M. T. Islam, and N. Misran, "A novel high-gain dual-band antenna for RFID reader applications," IEEE Antennas and Wireless Propagation Letters, Vol. 9, 653-656, 2010.
doi:10.1109/LAWP.2010.2055818

4. Koski, E., T. Bjorninen, L. Ukkonen, and L. Sydanheimo, "Radiation efficiency measurement method for passive UHF RFID dipole tag antennas," IEEE Transactions on Antennas and Propagation, Vol. 61, No. 8, 4026-4035, Aug. 2013.
doi:10.1109/TAP.2013.2261448

5. Zhang, J. and Y. Long, "A novel metal-mountable electrically small antenna for RFID tag applications with practical guidelines for the antenna design," IEEE Transactions on Antennas and Propagation, Vol. 62, No. 11, 5820-5829, Nov. 2014.
doi:10.1109/TAP.2014.2354412

6. Chen, W., Z. Niu, M. Li, Z. Li, Q. Xu, and C. Gu, "Design and evaluation of planar bifilar helical antennas for radio frequency identification tags," IEEE Antennas and Wireless Propagation Letters, Vol. 18, No. 12, 2642-2646, Dec. 2019.
doi:10.1109/LAWP.2019.2947168

7. Galehdar, A., D. V. Thiel, and S. G. O’Keefe, "Antenna efficiency calculations for electrically small, RFID antennas," IEEE Antennas and Wireless Propagation Letters, Vol. 6, 156-159, 2007.
doi:10.1109/LAWP.2007.891960

8. Wheeler, H. A., "The radiansphere around a small antenna," Proceedings of the IRE, Vol. 47, No. 8, 1325-1331, 1959.
doi:10.1109/JRPROC.1959.287198

9. McKinzie, W. E., "A modified Wheeler Cap method for measuring antenna efficiency," IEEE Antennas and Propagation Society International Symposium, 542-545, 1997.

10. Newman, E. H., E. Bohley, and C. H. Walter, "Two methods for the measurement of antenna efficiency," IEEE Transactions on Antennas and Propagation, Vol. 23, No. 4, 457-461, 1975.
doi:10.1109/TAP.1975.1141114

11. Rogers, R. L., D. P. Buhl, H. Choo, and H. Ling, "Size reduction of a folded conical helix antenna," IEEE Antennas and Propagation Society International Symposium, Vol. 4, 34-37, 2002.
doi:10.1109/APS.2002.1016920

12. Cho, C., J. Kang, and H. Choo, "Improved Wheeler Cap method based on an equivalent high-order circuit model," IEEE Transactions on Antennas and Propagation, Vol. 62, No. 1, 274-281, Jan. 2014.
doi:10.1109/TAP.2013.2287277

13. Schantz, H. G., "Radiation efficiency of UWB antennas," IEEE Conference on Ultra Wideband Systems and Technologies, 351-355, 2002.

14. Johnston, R. H. and J. G. McRory, "An improved small antenna radiation efficiecny measurement method," IEEE Antennas and Propagation Magazine, Vol. 40, No. 5, 1998.
doi:10.1109/74.735964

15. Rishani, N., F. Gourari, J. Dubouil, J. M. Laheurte, R. Shubair, and S. Abou Chakra, "Comparison of UHF RFID loop matching antennas based on various substrate-metal material combinations," IEEE Middle East and North Africa Communications Conference, 2018.

16. Mitsubishi paper mills limited., , Mitsubishi paper mills silver nano paticle ink [Online]., ‘Mitsubishi’, available from: https://www.mpm.co.jp/electronic/eng/silver-nano/index.html..

17. Impinj., , Monza 5 Tag Chip datasheet [Online], available from: https://support.impinj.com/hc/en-us/articles/202756948-Monza-5-Tag-Chip-Datasheet..

18. Zhang, J., S. Pivnenko, and O. Breinbjerg, "A modified Wheeler cap method for radiation efficiency measurement of balanced electrically small antennas," Proceedings of the Fourth European Conference on Antennas and Propagation, 2010.

19. Sarrazin, F., S. Pflaum, and C. Delaveaud, "Radiation efficiency measurement of a balanced miniature IFA-inspired circular antenna using a differential Wheeler Cap setup," International Workshop on Antenna Technology (iWAT), 64-67, 2016.

20. Vu, T. M., A. Diallo, C. Luxey, and G. Kossiavas, "Optimization of the size and the shape of a wheeler cap for mobile phone-antenna efficiency measurements," The Second European Conference on Antennas and Propagation, EuCAP, 1-6, 2007.

Dr. Nadeen Rishani

Dr. Jean-Marc Laheurte

Dr. Stephane Protat

Dr. Raed Shubair