Comparison of correlation algorithms between GTEM cell and semi anechoic chamber

The main purpose of GTEM cell as an alternative facility for EMC compliance testing is to accurately measure the radiated emission generated from an equipment-under-test (EUT). The open area test site (OATS) is the standard test facility for radiated emission measurements, thus the GTEM cell data have to be correlated to the OATS results. The correlation algorithms between GTEM cell and OATS such as 3, 6/9 and 15 position methods, etc., simulate the EM test for an EUT over the ground plane by using the power radiated from EUT located within the GTEM cell. This paper statistically verifies two well-known correlation algorithms, that is, 3 and 15 position algorithms by comparing the data obtained by the correlation algorithms at GTEM cell with the results measured with antenna at semi-anechoic chamber (SAC). Also, the results obtained by those correlation algorithms are compared with the theoretical values calculated from an ideal dipole model to minimize the effects due to any measurement uncertainty. From the results, it was found that the data obtained by the GTEM cell and those correlation algorithms have a strong correlation with the data at SAC. In addition, the EM data obtained by 3 and 6/9 position methods showed higher than those by the others at almost all frequencies.