Electromagnetic Compatibility Society - 7:PM, Wednesday, 16 October Experimental and Theoretical Analysis of Electromagnetic Shielding of Enclosures (Keeping Fields where they belong) Dr.Lothar (Bud) O.Hoeft, Independent Consultant, Distinguished Lecturer EMC Society Most electronic systems are packaged in some sort of enclosure providing mechanical and electromagnetic protection. The size and construction of the enclosure determines its electromagnetic performance. One use of conductive enclosures is to keep electromagnetic fields where they belong. The surface magnetic field attenuation (MFA) of a wide range of enclosures and panels has been measured by injecting a uniform current across the surface and measuring the ratio of the surface magnetic field to the magnetic field inside the enclosure. The speaker will discuss a simple theory developed to explain and extend the results. These measurements show that relatively simple structures provide on the order of 50 dB of attenuation for frequencies above 1 MHz. In well-constructed enclosures, joint resistance limited the electromagnetic performance. Current diffusion was not evident for frequencies above a few tens of kilohertz, except in panels with minimal metal content (metal screens and thin metal coatings). Aperture coupling could be accounted for using polarizability theory. Dr. Bud Hoeft received a B.S. and M.S. in physics from the University of Wisconsin and a PhD in physics and biophysics from Pennsylvania State University. In 1979, he completed a 25-year R&D career in the U.S. Air Force working on acoustical noise control, bionics, nuclear weapon simulation, pulse power technology and international R&D coordination. He joined BDM, where he was primarily concerned with helping designers build and test systems that are hard to electromagnetic effects. In 1994, he retired from BDM and became a private consultant. Dr. Hoeft is a Certified EMC Engineer. He has presented numerous papers and tutorials on shielding and electromagnetic effects at IEEE-EMC, NEM, Zurich-EMC, Wroclaw-EMC, IEE-EMC, Lightning and IICIT symposia. In 2001, he was appointed Distinguished Lecturer of the IEEE EMC Society. This meeting of the IEEE Central New England Chapter of the EMC Society will be held on Wednesday October 16, 2002 at EMC Corporation, 42 South Street, Hopkinton in the Corporate Auditorium Training Center Building. The technical presentation will commence at 7 PM,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. > Non IEEE-members are welcome. > > Boris Shusterman, vice-chair > [email protected] ------------------------------------------- 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: [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://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
