Has anyone investigated the difference in performance of different chamber sizes when performing the radiated immunity (-3) test at low frequencies (e.g., between 80 MHz and 100-150 MHz)? The field uniformity is calibrated in E-field, but I would expect the total EM field (E and H components) to have different distribution as a function of different chamber sizes. Specifically, keeping the distance between the antenna and the DUT constant at 3 m, I still expect different performances due to size (chamber loading the antenna and reflections/near field). Consequently, it seems that the interfering signal can be quite different in a small chamber vs. large chamber, with possibly large variations in the H-field components, even though they are both calibrated for the E-field uniformity, and both tests performed at the antenna distance of 3m.
I know of a case in which testing in a smaller (3m) chamber makes product consistently fail at significantly lower level than in a larger, 10 m chamber (6 V/m vs. nearly 10 v/m). Fixing a product to pass the 10 V/m level (required by the customer) in the large chamber seems to be relatively easy and inexpensive, while fixing it to pass the same level in a small chamber may be very costly and time consuming. Is there any precedence like in case of the radiated emission, where 10m results prevail in case of a dispute? Any papers to support or dismiss my expectation from above? Thanks, Neven This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
