Oops! I forgot the link to the EMC paper. It is: http://emcesd.com/pdf/emc99-w.pdf
Doug -------- Original Message -------- Subject: Shielded loop parasitic coupling List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Wed, 04 Jun 2008 19:39:59 -0700 From: Douglas Smith <d...@emcesd.com> <mailto:d...@emcesd.com> Reply-To: d...@dsmith.org Organization: D. C. Smith Consultants To: emc-pstc <emc-p...@ieee.org> <mailto:emc-p...@ieee.org> , SI-List <si-l...@freelists.org> <mailto:si-l...@freelists.org> Hi Everyone, I have posted the latest Technical Tidbit on my website http://www.dsmith.org . It should be interesting to EMC folks who use magnetic field probes and to SI people as well since magnetic loops are very useful at finding board layout issues by signal injection thorough mutual inductance. The link to the article is the picture at the bottom of the page at http://www.dsmith.org . I have two more Technical Tidbits coming on shielded magnetic loops. When the series of 4 articles is finished, it will be obvious that apart from measuring in the far field (in this case I mean much farther from the antenna than the size of the antenna which can be much further than the conventional definition of 1/6 wavelength) there are serious limitations on shielded magnetic loops due to their lack of E field rejection in many cases in the near field. You can also see my 1999 IEEE EMC Symposium paper at: Signal and Noise Measurement Techniques Using Magnetic Field Probes (~600K pdf file) Technical Tidbit - June 2008 The Square Shielded Loop - Part 2, Parasitic Coupling (Electric Field Shielding of Magnetic Loops Is Not Always Effective!) Abstract: Shielded magnetic loops are used to reduce electric field coupling to the loop and square magnetic loops are useful for coupling signals into a PCB or measuring noise in a circuit. However, significant electric field coupling can still occur with shielded loops. One case of electric field coupling between a pair of shielded loops is presented which results in a significant resonance between the shielded loops. Such a resonance can cause errors in signal injection used for troubleshooting circuits. Doug -- ___ _ Doug Smith \ / ) P.O. Box 1457 ========= Los Gatos, CA 95031-1457 _ / \ / \ _ TEL/FAX: 408-356-4186/358-3799 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-----( ) | o | Email: d...@dsmith.org \ _ / ] \ _ / Web: http://www.dsmith.org - ---------------------------------------------------------------- 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 emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc -- ___ _ Doug Smith \ / ) P.O. Box 1457 ========= Los Gatos, CA 95031-1457 _ / \ / \ _ TEL/FAX: 408-356-4186/358-3799 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-----( ) | o | Email: d...@dsmith.org \ _ / ] \ _ / Web: http://www.dsmith.org - ---------------------------------------------------------------- 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 emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
