On the Maximum Expected Electric Field in Electrically Small, Undermoded Enclosures

The aerospace EMC community is still seeking robust methods to predict the maximum expected field strength in avionics boxes and other electrically small enclosures. The authors use results of an experimental study on an aperture enclosure to show that frequency variance must be considered – in addition to Rayleigh statistics – when dealing with such under-moded enclosures. A statistical model based on Lyon's 1969 work on acoustic response variance in rooms is shown to be a significant improvement over the Rayleigh statistics model for predicting the maximum expected electric field response in electrically small enclosures.