My experience in almost thirty years of mil and aerospace EMC work is that few equipments fail above 1 GHz at 200 V/m. But that isn’t the whole story. Mil/aerospace equipment is extremely well shielded compared to commercial equipment, both in terms of equipment enclosures and cable shields. Also, generally speaking, the equipments operate at much lower speeds than what is state of the art in the commercial world. Finally, mil/aerospace equipment is designed for installation on and tested in the immediate proximity of a ground plane, which is absent in the commercial world. Designs with no ground plane require much better shielding that equipment near a ground plane, and as noted earlier, the mil/aerospace equipment has better shielding than commercial. So the net result is that I don’t think you can extrapolate mil/aerospace immunity at 200 V/m and predict commercial immunity as we ll. My prediction would be that commercial equipment doing roughly the same function as a mil or aerospace design would be susceptible at lower levels than the mil/aerospace equipment.
That being said, the test requirement is much more stringent than the environment in that a real radar has a microsecond long pulse at a kilohertz rep rate, so that error correction routines ought to be able to filter out any radar coupling. Software filtering is much less expensive than hardware. But the test requirement is square wave 1 kHz modulation – you won’t be able to take advantage of the low radar duty cycle in the test lab. Ken Javor Phone: (256) 650-5261 ________________________________ From: John McAuley <[email protected]> List-Post: [email protected] List-Post: [email protected] List-Post: [email protected] Date: Mon, 29 Sep 2008 22:18:26 +0100 To: <[email protected]> Subject: Immunity of commercial equipment to radar at frequencies over 5 GHz Dear Group I am seeking information on the immunity of commercial equipment to radar at frequencies over 5 GHz. The field strength will be in excess of 300 V/m. There is little information available on the immunity of commercial equipment to radar pulses at these high frequencies and levels. My guess is that equipment will be relatively immune given the bandwidth of IC technology. The rule of thumb for the bandwidth of IC technology is 10 or 20 times the bandwidth. There may, of course, be non linear out of bandwidth responses. >From a search on the web it appears that PCs will not exceed 4 GHz for some time based on the current state of the art 45 µm and 65 µm technology. What is the upper bandwidth of a 3 GHz PC? I would also assume that the high frequency clock is contained within the processor and would be relatively well protected? I would be interested to hear from military test labs that have experience of testing immunity of equipment to pulsed fields up to 18 GHz. How frequently do conventional circuits fail high level EMI testing? Many thanks for any information provided. Best regards John McAuley Compliance Engineering Ireland Ltd www.cei.ie <http://www.cei.ie> <http://www.cei.ie> [email protected] <mailto:[email protected]> <mailto:[email protected]> ***************************************************************** DISCLAIMER: The information contained in this e-mail may be confidential and is intended solely for the use of the named addressee. Access, copying or re-use of the e-mail or any information contained therein by any other person is not authorised. If you are not the intended recipient please notify us immediately by returning the e-mail to the originator ________________________________ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
