Radiated emissions test performance of the GHz TEM cell

The gigahertz transverse electromagnetic (GTEM) cell has recently been recognized as a competing technology for the accomplishment of electromagnetic compatibility (EMC) radiated emissions testing for the demonstration of compliance with commercial specifications. As a competing technology, the direct comparison of the performance of a GTEM, for such compliance measurements, to the results obtained from an open area test site (OATS) is an obvious and necessary step. The direct comparison of results of two series of tests is described. Two differing comparisons are described: three separate sets of reference dipole comparison measurements, and two full personal computer (PC) systems tested per the requirements of ANSI 63.4, Draft 11.4 on an OATS and in a GTEM. In addition to a direct comparison, the resultant data has been subjected to statistical analysis. The statistical analysis was performed on maximum electric field strength data comparing GTEM calculated levels with open area test site measured levels. Pearson´s correlation coefficient and the student-t distribution were used to analyze the data. Good agreement of results, both by direct comparison and by the statistical analysis have been found.<>