Statistical analysis of measured data concerning electromagnetic environment inside an experimental avionics bay and implications for testing

In this paper, results from a statistical analysis of measured data are presented that once again confirms the assumption that the electromagnetic environment (EME) inside avionics bays is statistically isotropic and randomly polarized. The conclusion is that reverberation chambers present a more adequate electromagnetic test environment to avionics boxes than ordinary plane-wave testing. It is also concluded that the low frequency limit for a statistically isotropic and randomly polarized EME for an avionics bay is well predicted as being 3 to 4 times the first resonance frequency of the avionics bay. Also found is that the variation in shielding. effectiveness is 20-60 dB depending on probe location, and that only for one illumination angle and polarization.