It is challenging to design a high-performance UHF RFID tag antenna on a liquid-filled bottle due to the high conductivity, high permittivity and the variety of liquids. A systematic way how to design a high-performance UHF RFID tag antenna on a liquid-filled bottle is presented. A simple design consisting of a folded dipole and a loop matching structure is first proposed for a tag antenna placed on a water bottle. A co-design approach is adopted to make the water and bottle surface become a part of the tag antenna to eliminate the significant influence of the environment. The measurement results at 915 MHz show that the reading range of the simple design can reach 8 m in the absence of the water bottle and reach 4.2 m when it is placed on a water bottle. The folded dipole on the water bottle is then optimized to improve the gain significantly, and a maximum gain of -5.54 dBi is achieved at 915 MHz. Furthermore, the impedance bandwidth for the tag antenna on the water bottle is greatly improved by increasing the number of loops in the impedance matching structure from one to three, and the -6 dB impedance bandwidth of over 100 MHz (simulation) or 84 MHz (experiment) is achieved. The reading range of 5.6 m is achieved when the tag antenna is placed on a water bottle at 915 MHz.
1. Konieczny, M., B. Pawlowicz, J. Potencki, and M. Skoczylas, "Application of RFID technology in navigation of mobile robot," 2017 21st European Microelectronics and Packaging Conference (EMPC) & Exhibition, 1-4, Warsaw, Poland, 2017.
2. Michael, K. and L. McCathie, "The pros and cons of RFID in supply chain management," International Conference on Mobile Business (ICMB’05), 623-629, 2005. doi:10.1109/ICMB.2005.103
3. Bjorninen, T., A. Z. Elsherbeni, and L. Ukkonen, "Low-profile conformal UHF RFID tag antenna for integration with water bottles," IEEE Antennas and Wireless Propagation Letters, Vol. 10, 1147-1150, 2011. doi:10.1109/LAWP.2011.2171911
4. Sohrab, A. P., Y. Huang, M. Hussein, M. Kod, and P. Carter, "A UHF RFID tag with improved performance on liquid bottles," IEEE Antennas and Wireless Propagation Letters, Vol. 15, 1673-1676, 2016. doi:10.1109/LAWP.2016.2521786
5. Bjorninen, T., L. Ukkonen, L. Sydanheimo, and A. Z. Elsherbeni, "Development of a low profile conformal UHF RFID tag antenna for identification of water bottles," 2011 IEEE International Symposium on Antennas and Propagation (APSURSI), 533-536, Spokane, WA, 2011.
8. Ellison, W. J., K. Lamkaouchi, and J.-M. Moreau, "Water: A dielectric reference," J. Molecular Liquids, Vol. 68, No. 2–3, 171-279, Apr. 1996. doi:10.1016/0167-7322(96)00926-9
9. Rao, K. V. S., P. V. Nikitin, and S. F. Lam, "Antenna design for UHF RFID tags: A review and a practical application," IEEE Transactions on Antennas and Propagation, Vol. 53, No. 12, 3870-3876, Dec. 2005. doi:10.1109/TAP.2005.859919
10. Meys, R. and F. Janssens, "Measuring the impedance of balanced antennas by an S-parameter method," IEEE Antennas and Propagation Magazine, Vol. 40, No. 6, 62-65, Dec. 1998. doi:10.1109/74.739191
11. Qing, X., C. K. Goh, and Z. N. Chen, "Impedance characterization of RFID tag antennas and application in tag co-design," IEEE Transactions on Microwave Theory and Techniques, Vol. 57, No. 5, 1268-1274, May 2009. doi:10.1109/TMTT.2009.2017288
12. Marrocco, G., "The art of UHF RFID antenna design: Impedance-matching and size-reduction techniques," IEEE Antennas and Propagation Magazine, Vol. 50, No. 1, 66-79, Feb. 2008. doi:10.1109/MAP.2008.4494504
13. Meier, A. S. and W. P. Summers, "Measured impedance of vertical antennas over finite ground planes," Proceedings of the IRE, Vol. 37, No. 6, 609-616, Jun. 1949. doi:10.1109/JRPROC.1949.233299