More accurate determination of chamber performance using SA measurements compared to computational results

The new EMC-Standards in Europe prescribe good agreement between measured and analytical calculated NSA (normalised site attenuation) for EMC emission test environments. However, those analytically calculated values are inaccurate and include approximations. This may lead to deviations of measured and calculated NSA of more than 4 dB even at an ideal open area test site. In this paper a method for the exact determination of the chamber performance is introduced. The measured SA-values are not normalized to NSA, but directly compared to numerical calculations. The accuracy of the numerical calculation is verified and the results are compared to the values given in the standards. The investigations are concentrated on different EMC antenna types