Efficient and accurate characterization techniques for small antennas

This project is carried out in collaboration between 3 Nordic universities: Helsinki University of Technology (HUT), Technical University of Denmark (DTU), Chalmers University of Technology (Chalmers), and Swedish private company Bluetest AB.  

Personnel  

Pertti Vainikainen, Professor, HUT, project coordinator
Tommi Laitinen, Senior Researcher, HUT
Olav Breinbjerg, Professor, DTU
Sergey Pivnenko, Associate Professor, DTU
Jeppe M. Nielsen, Research Assistant, DTU
Per-Simon Kildal, Professor, Chalmers
Jan Carlsson, Adjunct Professor, Chalmers
Charlie Orlenius, Chief Technical Officer, Bluetest  

Period  

January 2008 – December 2009. 

Funding  

Nordforsk - Nordic research board operating under the Nordic Council of Ministers for Education and Research. 

Background 

The research and development of wireless communications systems is driven by the need for higher data rates as well as by the miniaturization of the devices and antennas. These needs together with a variety of emerging wireless communications applications create a need for the use of new radio systems. In a likely scenario the number of radio systems integrated into a wireless communications device (WCD) will exceed 10 in future. These different radio systems operate at different frequencies utilizing different modulation techniques. The systems may vary from narrowband systems like GSM to wideband systems enabling higher data rates.

Due to the large number of different radio systems, and the technical differences of these systems, the research and development needs are great and multi-dimensional. From the radio system point of view, it is essential to understand the nature of the radio propagation channel and have a capacity to develop suitable antennas for base stations and mobile terminals. As an integrated part of this, it is also necessary to build capacity and knowledge on the techniques for the performance testing of these systems prior to their deployment, and antenna testing forms an important part of this.

Amid development of more sophisticated antennas and antenna systems, the antenna test requirements become increasingly complex. As the number of radio systems increase, the number of different tests required will also increase. For example, while the standard antenna test methods for WCDs for GSM900 and GSM1800 systems include only the total radiated power and the total isotropic sensitivity as figures of merit, the new radio systems employing more than 1 antenna in the mobile terminal clearly require new figures of merit to be considered.  

Problem formulation 

At present, there is a clear lack of understanding of the best practices of testing mobile terminal antennas for the different radio system. This lack is due to the fact that the issue is too large to be investigated by a single research group. The questions to be answered would be for example the following:

  1. What are the good figures of merit for mobile terminal antennas in different radio systems (GSM900, GSM1800, diversity system, MIMO system)? 
  2. What are the necessary accuracy requirements for determining these figures of merit? 
  3. Importantly, in relation to the previous two, what are the most efficient test techniques that provide a) the sufficient accuracy, b) shortest test time, c) reasonable test equipment cost?  

Objectives in brief  

The main objective of the project is, through research and development tasks and extensive experimental measurement campaigns, to achieve a joint Nordic understanding of the current status and the future prospects of three significant techniques for testing mobile terminal antennas in terms of their strengths and weaknesses, their applicability for different radio systems, and the typical, expected accuracies the techniques provide. The following techniques for testing antennas are considered: 1) the multi-probe antenna measurement technique, 2) the reverberation chamber technique, and 3) the traditional, accurate single-probe antenna measurement technique. The Nordic organizations involved in the project are the Radio Laboratory at Helsinki University of Technology (HUT) from Finland, the antenna group at Chalmers University of Technology and the spin-off company Bluetest (Chalmers/Bluetest) from Sweden, and the ElectroScience Section at Technical University of Denmark (DTU) from Denmark. Importantly, these three organizations have been performing pioneering world-class research on the three significant antenna test techniques as follows: HUT on a multi-probe antenna measurement technique, Chalmers/Bluetest on the reverberation chamber technique, and DTU on an accurate single-probe spherical near-field antenna test technique.

The secondary objective is to provide the PhD students in the three organizations with the possibility to get familiar with the three state-of-the-art small antenna measurements techniques. This is made possible for the PhD students through participations in the test campaigns to be carried out in the three organizations.  

Description of the participating research organizations  

 

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14 NOVEMBER 2019