Hi Neven, Agilent Technologies has two 3m chambers with ferrite floors - one in Colorado Springs and one in Loveland. The Loveland site used a flexible metal mesh over the ferrite that actually seemed to work pretty well during the NSA verification tests. I do recall you had to get the wrinkles out and ensure the edges were beyond the immediate "bounce zone". In Colorado Springs, we had a permanent ferrite floor and did not bother using a ground plane. While I was there, I found it actually compared very favorably to our 10m OATS (both with comb generator sources and real products). And yes, I know it's not supposed to - but we've got the data to support it! :-) Your mileage may vary! With a few exceptions, most other Agilent chambers had no floor ferrites.
Ken ___________________ Kenneth Wyatt Wyatt Technical Services LLC Woodland Park, CO [email protected] www.emc-seminars.com On Apr 30, 2010, at 12:34 PM, Neven Pischl wrote: Dear EMC-PSTC-ers, Has anyone used semi-anechoic chambers with permanently installed ferrite tiles in the floor between the antenna and the DUT for radiated-immunity and with a (re)movable conductive cover for the emission tests. I would love to make it work if possible, because it would make it so much easier to move and store the thin sheet metal or wire-mesh than moving the ferrite panels in and out for the immunity tests. Perhaps Laird Flectron copper-cloth might work, http://www.lairdtech.com/Products/EMI- olutions/Specialty-EMI-Solutions/Metallized-Fabric/ <http://www.lairdtech.com/Products/EMI- olutions/Specialty-EMI-Solutions/Metallized-Fabric/> We can have ferrites installed in a compact semi-anechoic chamber (3m test distance) flush with the rest of the GND-plane/floor, but I am not sure if there is a good way to put a sheet of metal (or a copper wire mesh/cloth) over it, overlap and make a reliable contact with the GND plane around the perimeter of the ferrites. Perhaps with an overlap of at least 6” (15cm) with the rest of the GND-plane, using a bunch of magnets around the perimeter to tie it to the GND plane. Long-term reliability is also my consideration. I appreciate if you have any experience you are willing to share. Thanks, Neven - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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]>
