Pulsed signals in reverberation chambers: Experimental analysis of transient peaks

In a reverberation chamber high field strengths can be generated with comparatively low input power. This makes them suitable for EMC testing with pulsed signals where field strengths of up to 600 V/m are common. It has been shown that due to the reverberant nature of such chambers high transient field strengths are possible. Transient peaks much higher than the stationary field have been encountered. This makes testing with pulsed signals in reverberation chambers difficult as over-testing could be an issue. In this paper an experimental analysis of pulsed signals in reverberation chambers is given with special interest in the transient part. Time-domain measurements are made in two chambers with vastly different sizes where transient peaks are determined with respect to the stationary field. A strong dependence between the stationary field and expected overshoot is discovered and comparisons between the chamber response to turned-on and turned-off excitations are made. A worst-case scenario is considered showing that the transient overshoot does not automatically imply over-testing.