A new method for developing reverberation chamber conditions

Summary form only given . A new way of stirring in reverberation chambers is presented. Reverberation chambers, used for EMC tests, are electrically large multimoded cavities that use either mechanical or frequency stirring to create a statistically uniform field. The new way of stirring that is presented depends on the fact that instead of having a mechanical stirrer inside a reverberation chamber one could have equal results by varying the dimensions of the chamber in an either random or deterministic way. Measurements made in a mobile screened room verify the validity of the proposed method. More specifically, a screened room with walls made of a special conducting cloth, made to act as a reverberation chamber, was used in order to make field measurements. The stirring was provided with the help of a ventilator placed outside the chamber at one comer making its walls move in a random manner and as a result varying its dimensions. A monopole antenna connected to a signal generator was used as a transmitter and an E-field probe as a receiver. The specification mentioned in IEC 61000-4 series requiring 12 of 16 measurements distributed uniformly over a test plane having a uniformity within 6 dB is also obtained. Finally the field PDF in the reverberation chamber shows a rather satisfying matching with the theoretical curve.