Field uniformity and isotropy investigation of Halmstad University's reverberation chamber : In collaboration with Halmstad University and Ericsson AB, Lund

Abstract: This thesis is the final module of the Master's program in Electronics Design at Halmstad University. The Master Thesis work is a part of an ongoing development of Halmstad University's reverberation chamber (RC), which is aimed at frequencies in the low GHz range. The development process has been passing in several phases. One phase is to design a mechanical stirrer system which was done by the work presented in another thesis work. The current phase, which is done by this thesis work, is to investigate electromagnetic field uniformity and isotropy while using tuned-mode (stepped stirrer). The frequency 2.4 GHz was chosen because, from one hand, it fits the capability of the assigned equipment for this thesis (spectrum analyzer, signal generator, antennas). On the other hand, it is the operating frequency of a wide range of WIFI and BlueTooth devices that need to be tested inside the RC to comply with the Electromagnetic Compatibility (EMC) standards. The measurement results verified, to a reasonable extent, the field uniformity and isotropy. The standard deviation of all measurements, taken from different eight positions with three different orientations of the receiving antenna, was 1.5dB. It is less than 3dB fulfilling the IEC 61000-4-21standards for frequencies above 400MGHz. Moreover, a quality factor degradation test was conducted, showing a 3.5 dB reduction of the received power when the chamber was loaded by organic material. The received power, while sweeping the bandwidth 800MHz-1.5GHz, was measured. These results indicate that at the resonance frequencies of the chamber, the received power is higher than that at non-resonance frequencies.