Theoretical and experimental analysis of the field-to-line coupling in a reverberation chamber

The coupling between a two-wire transmission line and the electromagnetic field inside a reverberation chamber is analysed. The chamber field is represented by the superposition of plane waves with random incidence. The signal, induced along the line by such a field, is analytically found under general load conditions for the line, including a strong mismatching. Therefore this approach allows the parasitic elements introduced by real terminations and by measuring sensors to be accounted for. The statistics of the current flowing into the line load are analysed in terms of the cumulative distribution function and in terms of the maximum-to-mean ratio, an important parameter in immunity tests. All results are compared with those experimentally obtained in a real reverberation chamber, showing a satisfactory agreement; a discussion about the overall measurement uncertainty is also reported. Finally, some advantages of the use of reverberation chambers for immunity tests are highlighted.