Correlation of Automotive Electromagnetic Emissions Measurements

Although automotive electromagnetic emissions measurements are conventionally carried out at a range of 10 m under semi-anechoic conditions, some standards permit 3 m measurements to be used if a 10 dB adjustment is applied to the limit. Experimental and theoretical studies have been used to investigate this approach, and to assess whether data recorded in a fully anechoic environment can be used in this manner. This work indicates that measurements at 3 m can provide more accurate electric field data and that the effect of the ground plane is small at this range. These studies also suggest that a 5 dB adjustment may be more appropriate to estimate emissions levels at the 10 m range.