Spherical Near Field Facility for Characterizing Random Emissions

In a previous paper, a new time domain near field (TDNF) method for characterizing random emissions has been presented [1]. This method, which extends classical antenna NF techniques to random emissions, is based on the measurement of the spatial coherence of the NF distribution over a sphere in a narrow frequency band. The present paper describes a spherical facility which has been specially designed for experimentally implementing this NF method. This new TDNF measurement technique has been experimentally validated on radiating devices such as GSM telephone handsets. It allows one to derive not only the total power radiated by a device under test, as it could be done in a reverberating chamber, but also to obtain the spatial distribution of the radiated field outside the measurement sphere and, more particularly the far-field (FF) radiation pattern.