Experimental verification of correlation algorithm between FAC and open area test site/SAC

Abstract

The main purpose of Fully Anechoic Chamber (FAC) as an alternative facility for EMC compliance testing is to accurately measure the radiated emission generated from equipment-under-test (EUT). The Open Area Test Site (OATS) is the standard test facility for radiated emission measurement, thus the FAC data have to be correlated to the OATS results. In this paper, it is statistically verified the newly proposed correlation algorithm between FAC and test facilities with ground plane such as OATS, semi-anechoic chamber (SAC) in order to use a FAC as an alternative facility for EMC compliance test. The algorithm is based on modeling of EUT as an equivalent set of multipoles. A sequence of E field measurements at FAC is then used to determine the equivalent dipole moments and relative phases for EUT. The dipole model then allows one to simulate the radiated emission from EUT over a ground screen. Thus, emission measurements over an OATS as called for by various standards may be simulated. This paper reviews the basics of the multipole model as it relates to FAC, the E field measurement scheme at FAC, and presents the results of EMI measurements at both FAC and SAC. The radiated emission test using the proposed algorithm requires fifteen E field values measured at nine positions around an arbitrary EUT located within FAC. Radiation from the reference radiator has been tested in order to statistically verify the proposed correlation algorithm between a FAC and the test facilities with ground plane.