Professor Per-Simon Kildal heads the antenna group at Chalmers University of Technology. The group has during the nineties performed a lot of research on the moment method and design of array antennas. However, since year 2000 the group has focused on wireless applications, and in particular the development of the reverberation chamber to a tool for characterizing mobile wireless terminals. The group consists at present of 1 full professor, 1 adjunct professor, 1 assistant professor, 1 postdoc, 2 Chalmers employed PhD students, and 4 external PhD students at research institutes and companies.
The reverberation chamber is a multimode metal cavity that has been used for EMC measurements for 25 years. The antenna group has since year 2000 developed it further to characterize the performance of small antennas and wireless terminals for mobile communications in environments with Rayleigh fading. The measurement capabilities include radiation efficiency, radiated power, diversity gain, MIMO system capacity and receiver sensitivity. In the latter case the reverberation chamber enable fast measurements of Bit Error Rate and Frame Error Rate, and thereby Total Isotropic Sensitivity. In addition, the terminals can be tested under realistic and continuous fading very similar to what is present in urban and indoor environments, referred to as Average Fading Sensitivity. The chamber is the only known measurement instrument for directly measuring diversity gain and channel capacity; the alternative being to drive measurement instruments around in an actual urban environment. The measurements can fast and easily be performed for different talk positions relative to a head phantom.
The spin-off company Bluetest AB was formed already in year 2000, and the measurement techniques is now starting to spread significantly on the world market.
The antenna group is a member of ACE - Antenna Center of Excellence, a European Network of Excellence, and contributes actively in the newly formed European School of Antennas (ESoA) by arranging two short courses and lecturing in two more. In one of these courses the group lecturers how to perform wireless measurements in reverberation chamber.
Drawing (above) and photo (below) of the Bluetest 850 Standard reverberation chamber, shown with open door. The drawing shows set-up for measuring MIMO system capacity, and the photo shows setup for measuring radiated power of mobile phone close to head phantom. The chamber size shown allow for use down to 850 MHz.
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