The research about the double ridge horn calibration in local EMC testing chambers Measurements and uncertainty evaluations

The accurate measurement of 1m antenna factor (AF) is a fundamental requirement for reliable EMC testing in RE102 followed by MIL-STD-461F. The double ridge horn (one of receiving antennas required by standard) with frequency 200MHz–1GHz is hard to transfer to calibration site for measuring because of its big dimension with 69.0cm by 94.5cm opening. In order to solve the problem and reduce the risk associated with transportation as well, a suitable indirect calibration method using a transfer antenna is described in the paper. At the frequency range from 200MHz to 1GHz, several experiments have been done and the results agree well with the calibration ones with the maximum discrepancy being 2.0 dB. A detailed experimental analysis is offered for estimating all the relevant uncertainty contributions and the expanded uncertainty is 1.7dB.