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.
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Artificial Electromagnetic Composite Structures in Selected Microwave Applications

Pekka Ikonen

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Electrical and Communications Engineering for public examination and debate in Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 30th of March, 2007, at 12 o'clock noon.

Overview in PDF format (ISBN 978-951-22-8677-5)   [1337 KB]
Dissertation is also available in print (ISBN 978-951-22-8676-8)

Abstract

Possible performance enhancement of selected microwave applications is studied using artificial electromagnetic composite structures. The following definition is adopted for artificial electromagnetic composites: If we combine two or more materials (e.g., embed metal inclusions in a dielectric matrix) to produce another material (effectively behaving as another dielectric or artificial magnetic material), this material is an artificial electromagnetic composite. By varying the inclusions and their position relative to each other it is possible to synthesize a wide variety of macroscopic material properties. Even properties that do not exist in the class of "conventional" or "natural" materials can be achieved with sophisticated design methods. This extended range of available material characteristics, or the possibility to synthesize "conventional characteristics" with more simple and cheap means, offers a new design dimension for microwave engineers.

In this thesis the focus lies in two subclasses of artificial electromagnetic composites: 1) Artificial magnetic composites; 2) Artificial dielectric composites. Most of the artificial magnetic composites considered in this work consist of periodically arranged, electrically small broken loops. The circulating currents induced to a large set of inclusions give rise to macroscopic effective permeability that exceeds unity under proper circumstances. Fundamental properties of artificial magnetic composites are studied, and the possibilities to utilize these composites as microstrip antenna substrates are explored. The obtained results indicate that artificial magnetic substrates containing only non-magnetic constituents offer no advantages in antenna miniaturization.

Artificial dielectric composites considered in this work are implemented using periodical lattices of thin conducting wires, possibly loaded with a reactive distributed impedance. The main features of so called wire medium and loaded wire medium are reviewed. Later such composites are used as artificial material for a beam shaping element in base station antenna applications. We also study plane-wave transmission through finite thickness slabs implemented using a periodical arrangement of metal wires and broken loops, and extend the vector circuit theory, previously introduced for isotropic and chiral slabs, to uniaxial and spatially dispersive magneto-dielectric slabs. Finally, the recently proposed theory of sub-wavelength field channeling is experimentally validated.

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

  1. S. Maslovski, P. Ikonen, I. Kolmakov, S. Tretyakov, and M. Kaunisto, Artificial magnetic materials based on the new magnetic particle: Metasolenoid, in Progress in Electromagnetics Research, PIER, EMW Publishing, Cambridge, USA, vol. 54, pp. 61-81, 2005. © 2005 EMW Publishing. By permission.
  2. P. M. T. Ikonen and S. A. Tretyakov, Determination of generalized permeability function and field energy density in artificial magnetics using the equivalent-circuit method, IEEE Transactions on Microwave Theory and Techniques, vol. 55, no. 1, pp. 92-99, 2007. © 2007 IEEE. By permission.
  3. P. M. T. Ikonen, S. I. Maslovski, C. R. Simovski, and S. A. Tretyakov, On artificial magnetodielectric loading for improving the impedance bandwidth properties of microstrip antennas, IEEE Transactions on Antennas and Propagation, vol. 54, no. 6, pp. 1654-1662, 2006. © 2006 IEEE. By permission.
  4. P. M. T. Ikonen, K. N. Rozanov, A. V. Osipov, P. Alitalo, and S. A. Tretyakov, Magnetodielectric substrates in antenna miniaturization: Potential and limitations, IEEE Transactions on Antennas and Propagation, vol. 54, no. 11, pp. 3391-3399, 2006. © 2006 IEEE. By permission.
  5. P. Ikonen, C. Simovski, and S. Tretyakov, Compact directive antennas with a wire-medium artificial lens, Microwave and Optical Technology Letters, vol. 43, no. 6, pp. 467-469, 2004.
  6. P. Ikonen, M. Kärkkäinen, C. Simovski, P. Belov, and S. Tretyakov, Light-weight base station antenna with artificial wire medium lens, IEE Proceedings - Microwaves, Antennas and Propagation, vol. 153, no. 2, pp. 163-170, 2006. © 2006 The Institution of Engineering and Technology (IET). By permission.
  7. P. Ikonen, M. Lapine, I. Nefedov, and S. Tretyakov, Vector circuit theory for spatially dispersive uniaxial magneto-dielectric slabs, in Progress in Electromagnetics Research, PIER, EMW Publishing, Cambridge, USA, vol. 63, pp. 279-294, 2006. © 2006 EMW Publishing. By permission.
  8. P. Ikonen, P. Belov, C. Simovski, and S. Maslovski, Experimental demonstration of subwavelength field channeling at microwave frequencies using a capacitively loaded wire medium, Physical Review B, vol. 73, 073102, 2006. © 2006 American Physical Society. By permission.

Errata of publication 5

Keywords: broken loop, antenna miniaturization, wire medium, beam shaping, vector circuit, near field channeling

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© 2007 Helsinki University of Technology

Last update 2011-05-26