Radiated emissions test correlation between G-TEM, SAC and OATS facilities using digital phones

The author reports on the results of a correlation exercise comparing radiated emissions measurements obtained at three different kinds of facilities: a GHz transverse electromagnetic (G-TEM) cell, a semianechoic chamber (SAC), and an open area test site (OATS). A source with a data cable which must exit the cell is used. The test objects were digital phones. These telephones receive their power and communicate over an unshielded twisted pair cable. The cable must pass out of the cell and to a switch simulator, which maintains the telephone in its operation state. Several steps taken to improve the correlation between these various radiated emissions test facilities are reviewed. The correlation between the G-TEM and OATS is found to be generally better than 4.5 dB. For most frequencies the correlation is better than 2.5 dB