Jeff Chambers writes: >> This removes the 'line of sight' gap into the enclosure. Does this improve the attenuation? Intuitively it should, but if the leakage occurs because of the interruption in shielding conductivity and hence current flow at the seam, it won't. <<
I've run into this misapprehension before, and I agree with you that the RF leakage occurs due to a difference in potential across the seams (and a resultant current flow). You can easily demonstrate this and get people to stop trying it. However, at a sufficiently high frequency, the overlap acts as a waveguide terminated in an open circuit, and leakage will from that point vary cyclically as the waveguide mode matches or does not match the radiating configuration. The only reason it's beyond "line-of-sight" here, is that light is absorbed. Make the lid and cabinet really good mirrors, and light can be reflected around the aperture. Cortland 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
