Effects of Frequency Stirring on Reverberation Chamber Testing: An Analysis as a Radiation Problem

The effects of frequency stirring on the statistics of the currents induced on an equipment-under-test (EUT) placed in a reverberation chamber field are analyzed. A reciprocal approach that relates the received currents in a susceptibility test to the frees-pace input impedance presented by the EUT when excited at the test point is used. An analytical expression is then derived to give the distribution functions of the induced currents under frequency stirring that accounts for the frequency dependence of the EUT radiation characteristics. A numerical study of shielding-box EUTs with coupling apertures shows that the changes in the EUT test-port input impedance with frequency yield non-Rayleigh current statistics when frequency stirring is used. It is unlikely that a single distribution family with a limited number of parameters can be fit to the current statistics with EUTs of arbitrary volume, coupling aperture, and measurement probe configurations.