Low-Frequency Theoretical Analysis of a Source-Stirred Reverberation Chamber

Theoretical analysis of a reverberation chamber excited through the source-stirring technique at low frequency is presented. A complete analytical solution returns quickly the electromagnetic field inside the chamber thanks to an efficient computation technique for the slowly convergent triple series. The stirring function is accomplished by 62 monopole antennas, irregularly distributed on the chamber walls, and subsequently, fed two at a time for a total of 1891 combinations. At first, the empty chamber is characterized, as usually it is done for any test site and then a receiving loop is considered in the chamber working volume to simulate a device under test (DUT) and the induced voltage is studied in terms of amplitude and phase. The analytical approach allows to account for all mutual couplings between transmitting antennas and the receiving structure through the computation of all self and mutual impedances. We demonstrate that the contribution of chamber irrotational modes cannot be neglected in the computation of both antenna input impedance and DUT-induced voltage. The present study highlights the capability of source stirring to change the field amplitude and orientation in the undermoded condition. This advantage takes also benefit from the use of an out-of-phase feeding for each pair of active antennas, achieving a higher DUT-induced voltage.