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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Evaluation of Performance of Mobile Terminal Antennas

Kati Sulonen

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 2nd of July, 2004, at 12 o'clock noon.

Overview in PDF format (ISBN 951-22-7164-8)   [1259 KB]
Dissertation is also available in print (ISBN 951-22-7163-X)

Abstract

Fast development of new mobile communications equipment results in demand for fast and reliable evaluation methods to estimate the performance of mobile terminals because the performance of antennas located on the terminals varies in different multipath propagation environments. Two methods presented in this thesis provide new possibilities in antenna design because, from now on, the performance of new antennas can be tested already before a prototype antenna is constructed by using existing radio channel libraries and simulated radiation patterns of the antennas. The performance can be estimated by calculating the mean effective gain (MEG) of the antenna using the elevation power distribution or by a plane wave -based method using sets of incident plane waves and the radiation pattern of an antenna. In addition to different propagation environments, the effects of the user on performance can be included in the evaluation.

In this thesis, estimating the MEG of different antennas using the elevation power distribution and the power patterns of the antennas is shown to be an accurate and fast method by comparing the results with direct radio channel measurements. The mean difference between the methods is −0.18 dB with standard deviation of 0.19 dB. The usefulness of the evaluation method is demonstrated by evaluating the performance of several antennas located on mobile terminals. The antenna evaluation provided important and unique knowledge of the effect of both the environment and the user on performance. Because in calculating the radiation efficiency of the antenna we assume uniform incident field, the efficiency can result in a performance estimation that does not correspond to real usage situations. Therefore, including the environmental effects in the evaluation procedure is important, although the effect of the antenna is more important than the effect of the environment on MEG. It was noticed with calculated Gaussian-shaped beams that tilting or changing the beamwidth of a mobile terminal antenna has an effect of about 2 dB on MEG in multipath environments. Matching the polarization of the antenna to that of the environment can improve the performance more.

A novel incident plane wave -based tool has been developed for evaluating the performance of antenna configurations designed for diversity and Multiple-Input Multiple-Output (MIMO) systems. In this thesis, the instantaneous joint contribution of incident field consisting of a number of extracted plane waves and the complex three-dimensional radiation pattern of the antenna is shown to be accurate and extremely fast way to estimate the diversity advantages of different antenna configurations in time-variable radio channels. The difference between the diversity gains achieved by the plane wave -based method and by the direct radio channel measurements is on average less than 0.9 dB. Moreover, the radio channel can be exactly the same for all antenna configurations under test.

Furthermore, this thesis includes evaluation of the performance of different MIMO antenna configurations. The studied antenna configurations have been selected from the 16×64 MIMO channel measurement data. A novel way of using one omnidirectional reference antenna in a normalization procedure is shown to be reasonable especially in cases of antenna arrays consisting of directive elements. Three different propagation environments are used as evaluation platforms. The azimuth orientation of mobile terminal antennas may influence the performance of a MIMO antenna configuration significantly. In MIMO configurations compact dual-polarized receiving antennas provide capacity performance almost equal to the arrays employing single polarization.

This thesis consists of an overview and of the following 6 publications:

  1. Sulonen K. and Vainikainen P., 2003. Performance of mobile phone antennas including effect of environment using two methods. IEEE Transactions on Instrumentation and Measurement 52, number 6, pages 1859-1864. © 2003 IEEE. By permission.
  2. Sulonen K. and Vainikainen P., 2001. Effects of antenna radiation pattern on the performance of the mobile handset. Proceedings of the 2001 IEEE Antennas and Propagation Symposium Digest. Boston, USA, 8-13 July 2001, volume 3, pages 354-357. © 2001 IEEE. By permission.
  3. Kalliola K., Sulonen K., Laitinen H., Kivekäs O., Krogerus J. and Vainikainen P., 2002. Angular power distribution and mean effective gain of mobile antenna in different propagation environments. IEEE Transactions on Vehicular Technology 51, number 5, pages 823-838. © 2002 IEEE. By permission.
  4. Suvikunnas P., Sulonen K., Villanen J., Icheln C., Ollikainen J. and Vainikainen P., 2004. Evaluation of performance of multi-antenna terminals using two approaches. Proceedings of the 21st IEEE Instrumentation and Measurement Technology Conference (IMTC 2004). Como, Italy, 18-20 May 2004, paper IM04-4183. © 2004 IEEE. By permission.
  5. Sulonen K., Suvikunnas P., Vuokko L., Kivinen J. and Vainikainen P., 2003. Comparison of MIMO antenna configurations in picocell and microcell environments. IEEE Journal on Selected Areas in Communications: MIMO Systems and Applications 21, number 5, pages 703-712. © 2003 IEEE. By permission.
  6. Sulonen K., Suvikunnas P., Kivinen J., Vuokko L. and Vainikainen P., 2003. Study of different mechanisms providing gain in MIMO systems. Proceedings of the 58th IEEE Vehicular Technology Conference (VTC-2003 Fall). Orlando, USA, 4-9 October 2003, paper 03C_01.pdf. © 2003 IEEE. By permission.

Errata of publications 1, 2, 4 and 5

Keywords: mobile, antenna, performance, MEG, diversity, MIMO, radio channel measurements, incident field

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© 2004 Helsinki University of Technology

Last update 2011-05-26