The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
Aalto

Performance Enhancement of Small Antennas and Applications in RFID

Mervi Hirvonen

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Electronics, Communications and Automation for public examination and debate in Auditorium S5 at Helsinki University of Technology (Espoo, Finland) on the 7th of October, 2008, at 12 noon.

Overview in PDF format (ISBN 978-951-38-7109-3)   [510 KB]
VTT Publications 688, ISSN 1455-0849

Dissertation is also available in print (ISBN 978-951-38-7108-6)
Copyright © 2008 VTT Technical Research Centre of Finland
VTT Publications 688, ISSN 1235-0621
VTT-PUBS-688
TKK-DISS-2511

Abstract

The focus of this thesis is on the performance enhancement of small antennas and design and verification of antennas for radio frequency identification (RFID) and wireless sensors. The work is presented in eight scientific papers and in a summary, which introduces relevant fundamental concepts and previous work done in the field of small antennas.

Previously, several performance enhancement methods have been proposed to improve the antenna performance especially in mobile communication applications. However, solutions for the fundamental small antenna problem, high reactive energy and low radiation resistance, which in practice lead to narrowband and low efficiency operation, are rarely provided. In this thesis, alternative methods to alleviate the high reactive energy and low radiation resistance like material loading, non-Foster tuning and multi-port loading are discussed.

Also, lately antennas for RFID and wireless sensor applications have gained growing interest. However, several characteristic design features exist for these antennas. Especially, the concept of platform insensitivity is essential and discussed in detail. Also, antenna designs and dual-band tuning technique applicable to RFID antennas are presented. In addition, wireless measurement techniques for RFID antenna verification are reported.

This thesis consists of an overview and of the following 8 publications:

  1. M. Hirvonen and J. C.-E. Sten, Power and Q of a horizontal dipole over a metamaterial coated conducting surface, IEEE Transactions on Antennas and Propagation, vol. 56, no. 3, pp. 684-690, March 2008. © 2008 IEEE. By permission.
  2. M. Hirvonen and S. A. Tretyakov, Near-zero permittivity substrates for horizontal antennas: Performance enhancement and limitations, Microwave and Optical Technology Letters, vol. 50, no. 10, pp. 2674-2677, Oct. 2008. © 2008 John Wiley & Sons. By permission.
  3. M. Hirvonen, A. Hujanen, J. Holmberg and J. C.-E. Sten, Bandwidth limitations of dipoles matched with non-Foster impedances, Proceedings of the Second European Conference on Antennas and Propagation (EuCAP 2007), Edinburgh, UK, 11-16 November 2007. © 2007 The Institution of Engineering and Technology (IET). By permission.
  4. J. C.-E. Sten and M. Hirvonen, Impedance and quality factor of mutually coupled multiport antennas, Microwave and Optical Technology Letters, vol. 50, no. 8, pp. 2034-2039, August 2008. © 2008 John Wiley & Sons. By permission.
  5. J. C.-E. Sten and M. Hirvonen, Decay of groundplane currents of small antenna elements, IEEE Antennas and Wireless Propagation Letters, vol. 4, pp. 82-84, 2005. © 2005 IEEE. By permission.
  6. M. Hirvonen, P. Pursula, K. Jaakkola and K. Laukkanen, Planar inverted-F antenna for radio frequency identification, Electronics Letters, vol. 40, no. 14, pp. 848-850, July 2004. © 2004 The Institution of Engineering and Technology (IET). By permission.
  7. M. Hirvonen, K. Jaakkola, P. Pursula and J. Säily, Dual-band platform tolerant antennas for radio-frequency identification, IEEE Transactions on Antennas and Propagation, vol. 54, no. 9, pp. 2632-2637, Sep. 2006. © 2006 IEEE. By permission.
  8. P. Pursula, M. Hirvonen, K. Jaakkola and T. Varpula, Antenna effective aperture measurement with backscattering modulation, IEEE Transactions on Antennas and Propagation, vol. 55, no. 10, pp. 2836-2843, Oct. 2007. © 2007 IEEE. By permission.

Errata of publication 1

Keywords: small antennas, RFID, wireless sensors, quality factor, near-zero permittivity, non-Foster tuning, multi-port antennas, platform insensitivity, dual-band, backscattering measurement

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© 2008 Helsinki University of Technology

Last update 2011-05-26