Laboratory data demonstrate the need for an international standard on EMC antenna calibration
KEN HALL
THIS ARTICLE PRESENTS the FINAL results of the antenna inter-laboratory calibration comparison that was spearheaded by Hewlett-Packard between September 2002 and February 2005. Six above 1-GHz antennas were circulated to eleven antenna calibration facilities. The summary results are presented here.
INTRODUCTION
An inter-laboratory comparison of above 1-GHz antenna calibration was initiated in September 2002, managed by Hewlett-Packard. This study was initiated because data from six different calibrations of a horn antenna (Figure 1) varied significantly from data obtained in a study by NPL (National Physical Laboratory) and in a very controlled study of an X-band horn antenna carried out by NIST. There were from four to six antennas circulated to ETS-Lindgren, USA; Austrian Research Center, Austria; Schwarzbeck, Germany; CONFORMITAS Ing., Germany; Rohde & Schwarz, Germany; Rolf Heine, Germany; NPL, UK; CRL, Japan; Akzo Nobel, Japan; Liberty Labs, USA and NIST, USA. Schwarzbeck has added two additional antennas to the round robin. Ten laboratories completed the calibrations. Results show worst case deviations between laboratories to be greater than 9 dB. Antennas and calibration laboratories have been coded for privacy.
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