RMCEMC Feb Bonus Meeting

Our last meeting was..

Antenna Behavior and Use - (What Really goes on during a test?!)
Understanding EMI Shield Behavior in Real Product Environments

Download the presentations here
Pictures of the meeting

Presenter: Colin Brench, HP Principal Member of technical Staff (Bio)

Date : Feb 5th 2003

What we saw: The officers of the RMCEMC Society would first like to thank Colin Brench for delivering two papers in an EMC double header. Some brave souls defied the elements - yes, it actually snowed! - and benefited from two excellent presentations. In the first presentation Antenna Behavior and Use - (What Really goes on during a test?!) Colin explored the history of measurement techniques and looked at the magnitude of the errors introduced, and showed how through the use of computational techniques this problem is slowly being addressed. The first anomaly the Colin explored was the ubiquitous Antenna Factor. A classic case of bureaucracy over physics, Colin showed how having a constant antenna factor is really incorrect when testing a actual product. One attendee commented that if this test metric was properly implemented that "We would end up with more failing products!" much to the dismay of the other attendees. Colin then explored the behaviors of a number of different antennas in the EMC test environment. and showed the errors involved as a result of the disconnect between the ways the antennas are designed, used and calibrated. All in all a very informative and illuminating discussion.

In a feat of speaker fortitude Colin, after only a 5 min break presented Understanding EMI Shield Behavior in Real Product Environments . As EMC folks we know that EMI shielding is a mainstay of EMI control. Frankly without it regulatory life would be very difficult indeed. However, there is often opposing requirements that are imposed on enclosure design. The EMC Engineer tries had to have no holes or slots but then the Mechanical Engineer insists on adding holes and slots to cool the electronics. In this presentation test data and modeling were used to show and explain some of commonly seen but miss-understood shielding problems. Typical cases were 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. Colin also demonstrated the errors in using the existing SE equations and showed that there may be situations when an EMI shield can be working much better than thought and under these conditions larger apertures are possible. To round off the evening, Colin showed some nifty simulation animations that showed the effects of cables, slots and even mounting ears.

Thanks Colin for a great show!!

Speaker Bio

Colin Brench has been working for Hewlett-Packard (via Digital Equipment Corp., and 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 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 over 20 technical papers and articles. In addition, he holds ten patents for various methods of EMI control. He is a NARTE certified EMC Engineer, a member of the Applied Computational Electromagnetics Society (ACES) and the IEEE EMC Society. He is active in the IEEE EMCS TC-9 and ANSI ASC63 SC-1 committees. In March of 2001, Colin was appointed to serve as a Distinguished Lecturer for the IEEE EMC Society in 2001 and 2002

Cost: Free. This meeting is open to all interested parties. You do not need to be an IEEE member to attend. However we encourage you join the IEEE EMC Society to help sponsor meetings such as these.

PICTURES FROM THE MEETING