Hi Everyone, I have been busy again writing another tech article, this one shows another manifestation that metal planes in close proximity can be tightly coupled at high frequencies. Coupling between equipment cabinets and the interaction with equipment grounding cables is explored using computer simulation.
Abstract: Metal planes in close proximity, whether circuit boards or sheets of metal, are tightly coupled at high frequencies. The frequencies involved need not be all that high in some instances. Adjacent equipment cabinets are one such case. Computer simulation is used to show that noise or EMI arriving at one cabinet over equipment cables can strongly couple to an adjacent cabinet, possibly affecting operation. The article is linked from a drawing of two cabinets with grounding conductors at the bottom of the index page at my website: http://emcesd.com In the article I discuss currents in the frequency domain. The article contains a link to a paper I just posted for those interested titled "Computer Simulation of ESD and Lightning Events" which I wrote for the EOS/ESD Symposium in 1986. The paper discusses a similar case to this month's Technical Tidbit (above) except voltages in the time domain are discussed. Although tech has advanced quite a bit since then, there are many good design points in the paper. It is intersting to note that the Cray computer I often used for simulations in the mid-80's had just a tiny fraction of the computing power of the PowerMac dual G4 I use for simulations these days. I remember running simulations that took 20 minutes of Cray time and cost US$600 for each run! I could run the same simulation these days in a matter of seconds (16 giga-floating point operations/sec). Techonogy has come a long way! 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: [email protected] \ _ / ] \ _ / Website: http://www.dsmith.org This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
