Statistics of the Current Induced Within a Partially Shielded Enclosure in a Reverberation Chamber

Abstract

The statistics of the current induced on conducting wires and surfaces within a partially shielded enclosure by aperture coupling of an ideally random, mechanically stirred reverberation chamber electromagnetic field has been considered. A robust discretization of the plane-wave spectral representation of the chamber field confirms that the magnitude of the induced current at a test point follows a Rayleigh distribution provided that the equipment under test (EUT) is composed entirely of electromagnetically linear materials and mechanical or spatial stirring of the external chamber field is used, independent of the sizes of the EUT and coupling aperture. The discrete spectrum gives an efficient method to numerically find the statistics of the currents on or within arbitrarily shaped EUTs. Experimental measurement of the induced currents on a sample EUT within a mechanically stirred reverberation chamber confirms the validity of the discrete-plane-wave spectral method of predicting the current statistics at low and high frequencies. Addition of frequency stirring introduces a fundamental difference in the operation of a reverberation chamber test that leads to non-Rayleigh sample statistics when highly resonant EUTs are considered.