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CONCLUSIONS AND FUTURE WORK

The electrical properties of material, the identified object is made of, change the characteristics of the
transponder antenna fastened to the object. To maintain the performance of the RFID system in the
vicinity of challenging materials the antenna element has to be tuned according to application. To test
the performance of these application specific antennas for the paper reel application the
electromagnetic model for the reel was created. The dielectric properties for the model were taken
from the literature. Little information of dielectric properties of paper at higher frequencies is
available.

First the field attenuation in paper was studied by simulating the coupling between two dipoles with
paper in between. The attenuation increased from 3 dB to 25 dB from the free space attenuation value
as the loss tangent value increased from 0.05 to 0.5. In the means of antenna separation in free space
this means that the distance between the antennas is increased from 0.53 meters to 0.8-8 meters.

Second the effect of change in dielectric properties of paper to the properties of dipole antenna inserted
inside the paper reel was analyzed. Increasing the relative dielectric constant of the paper lowered the
resonant frequency of the dipole antenna. The change in loss tangent of the paper did not affect the
resonant frequency remarkably, but the change in antenna matching was noticeable.
In the future the research will concentrate on testing new application specific antenna geometries for
the paper reel RFID transponders with the proposed model.

REFERENCES

Finkenzeller K. (2003), RFID Handbook, 2nd Ed., John Wiley & Sons Inc., New York, USA
Niskanen K. (1998), Papermaking Science and Technology, Book 16: Paper Physics, Fapet,
Helsinki, Finland
Simula S., Varpula T., Ikalainen S., Seppa H., Paukku A., Niskanen K. (1999), Measurement of
the Dielectric Properties of Paper, Journal of Imaging Science and Technology, 43:5, 472-477.
Matsuda S. (2002), Handbook of Physical and Mechanical Testing of Paper and Paperboard,
2nd Ed., Dekker, New York, USA
Balanis C.A. (1997), Antenna Theory, Analysis and Design, 2nd Ed., John Wiley & Sons, Inc.,
USA

Keskilammi M., Salonen P., Sydanheimo L. and Kivikoski M. (2000), Radio Wave Propagation
Modeling in Paper Reel for Novel Radio Frequency Identification System, IEEE, JamCon2000,
Technology for Economic Development, Aug. 11-13, 2000, Ocho Rios, Jamaica