Determination of radiated emissions of an electrically large EUT: Simulation and experiment

The radiated emission testing of an electrically large equipment under test (EUT) has been carried out in a mode stirred chamber and a fully anechoic room. The radiation pattern of a rectangular metallic enclosure with a rectangular slot was measured, simulated and compared. The model of the EUT was then used for a statistical analysis of the expected value of the maximum directivity from 1GHz to 6GHz by numerical simulation. The statistical properties of the simulated directivity matches well with theoretical derivations. The results reveal that the expected value of the maximum directivity could be assumed as a function of electrical size of the EUT. The long term aim of the investigation is the estimation of the directivity of EUTs to correlate measurements of radiated emissions of electrically large EUTs in different test environments. By knowledge of directivity values and the measured total radiated power in an alternative test site, the maximum electric field strength of the EUT could be determined.