volume | PIER Journals

Abstract

The T-match feed is a useful impedance matching tool for dipole antennas, especially for electrically short dipoles with capacitive loads. The Uda model has been extensively tested for accuracy in the literature for the special case of the folded dipole, but not for the more general T-match dipole, which is often used for RFID antenna design. We investigate the accuracy of the Uda model for this more general case and show that aspects of the model become inaccurate for a number of practical scenarios. Nevertheless, we show that the model can still be used as a guide to T-match dipole designs.

1. Uda, S. and Y. Mushaike, Yagi-Uda Antenna, 119-131, Sasaki Printing and Publishing Co., Tokyo, 1954.

2. Wolff, E. A., Antenna Analysis, John Wiley & Sons, Inc., 1966.

3. Balanis, C. A., Antenna Theory, Analysis and Design, 3rd Ed., John Wiley & Sons Inc., New York, 2005.

4. Thiele, G. A., E. P. Ekelman, and L. W. Henderson, "On the accuracy of the transmission line model of the folded dipole," IEEE Trans. Antennas Propagation, Vol. 28, 700-703, 1980.
doi:10.1109/TAP.1980.1142400

5. Clark, A. R. and A. P. C. Fourie, "An improvement to the transmission line model of the folded dipole," IEE Proceedings --- H, Vol. 138, No. 6, December 1991.

6. Marrocco, G., "The art of UHF RFID antenna design: Impedance-matching and size-reduction techniques," IEEE Antennas & Propagation Magazine, Vol. 50, No. 1, Feb. 2008.
doi:10.1109/MAP.2008.4494504

7. Choo, M., J. Ryoo, J. Hong, H. Jeon, C. Choi, and M. M. Tentzeris, "T-matching networks for the efficient matching of practical RFID tags," Proceedings of the 39th European Microwave Conference, 5-8, Rome, Italy, Oct. 1, 2009.

8. Tai, C. T., "Theory of terminated monopole," IEEE Transactions on Antennas and Propagation, Vol. 32, No. 4, Apr. 1984.

9. Wadell, B., Transmission Line Design Handbook, Artech House, 1991.

10. Lampe, R. W., "Design formulas for an asymmetric coplanar strip folded dipole ," IEEE Trans. Antennas Propagation, Vol. 33, No. 9, 1028-1031, 1985.
doi:10.1109/TAP.1985.1143698

11. Lampe, R. W., "Corrections to design formulas for an asymmetric coplanar strip folded dipole," IEEE Trans. Antennas Propagation, Vol. 34, No. 4, 611, 1986.
doi:10.1109/TAP.1986.1143841

12. Mohammed, N., K. Demarest, and D. Deavours, "Analysis and synthesis of UHF RFID antennas using the embedded T-match," 2010 IEEE International Conference on RFID, Orlando, Fl, April 4-16, 2010.

13. Alien Technology, , Higgs-2 product overview, July 2008.

14. Texas Instruments TI UHF Gen 2 IC --- Reference Guide, 1st Ed., Dallas, TX, June 2006.

Professor Kenneth R. Demarest

Dr. Daniel D. Deavours