Central New England Chapter of EMC Society - meeting on March 13 Electromagnetic Compatibility Society - 7:00PM, 13 March Understanding EMI Shield Behavior in Real Product Environments Colin Brench, Compaq Computer Corporation, Distinguished Lecturer EMC Society
EMI shielding is a mainstay of EMI control. Frequently the design of the cooling or other apertures in a given enclosure is driven by the EMI requirements. This can result in compromised thermal and/or acoustic behavior and may mandate larger, noisier fans to meet other environmental needs. The well-established "Shielding Effectiveness" equations have their place, but they also have their limitations. In this presentation test data and modeling are used to show and explain some of commonly seen but mis-understood shielding problems. Typical cases will be presented including the effects of internal and external cables when located close to an array of apertures. Any proximal conductors can influence the shielding performance of an enclosure, and can create windows where the shielding is much lower than anticipated resulting in excessive emissions. There are also situations when an EMI shield can be working much better than thought and under these conditions larger apertures are possible. This may permit the use of smaller fans resulting in lower noise and/or less expensive construction details. Designing appropriate EMI shields is a major task for EMC engineers and understanding their true behavior is key to achieving this goal. Colin Brench has been working for Digital Equipment Corp., now Compaq Computer Corporation, for 16 years, where he is a Principal Member of the Technical Staff. He has responsibility for EMC product design, and the development of EMC modeling capabilities in the High Performance Server Division. Colin has been particularly active in the area of antenna and shielding behavior since the early 1970's. Colin has presented numerous EMC training classes that embrace a broad range of topics ranging from microprocessor packaging, through printed circuit module issues, to system design and shielding. In many of these classes explanations are clarified with a combination of computer generated simulations and data from measurements. Colin is a co-author of the book, EMI/EMC Computational Modeling Handbook (Kluwer Academic, 2nd Edition 2001), and has authored well over 20 technical papers and articles. In addition, he holds nine patents for various methods of EMI control. He is a NARTE certified EMC Engineer, a member of the IEEE EMC Society, and is active in the TC-9 and ANSI ASC63 SC-1 committees. In March of 2001, Colin was appointed a Distinguished Lecturer for the IEEE EMC Society. This meeting of the IEEE Central New England Chapter of the EMC Society (CNEC, EMCS) will be held on Wednesday March 13, 2002 at EMC Corporation, 42 South Street, Hopkinton in the Corporate Auditorium Training Center Building. The technical presentation will commence at 7PM, and refreshments will be available at 6PM. Directions: From Rte. 495 North or South take exit 21B to South Street. At first traffic light make left turn (Note: This is on South direction side of Rte. 495). EMC Corporation is at second driveway on right. For further information contact John Clarke at (508) 362-7195 or the meeting host Boris Shusterman at (877) 362-2887 ext.77517. If neither available leave message and calls will be returned. ------------------------------------------- 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: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
