Finding frequencies of enhanced electromagnetic coupling to electronic devices by the use of mode stirred reverberation chambers

We have measured the electromagnetic absorption in reverberation chambers for two RFID tags. This is done to find frequencies at which they may be vulnerable for high power microwaves. We compare two expressions for the absorption cross section for the investigated system, and the corresponding absorption cross section ratio. It turns out that it is enough to investigate the relative change in the ensemble average of the recorded power in the reverberation chamber to find the relevant frequencies.