Technical sessions abound at 2007 EMC Symposium
IEEE EMC Symposium, Hawai’i Convention Center, Honolulu, HI. www.emc2007.org.
Martin Rowe, Senior Technical Editor -- Test & Measurement World, 7/11/2007 1:55:00 PM
The technical sessions and trade show of the 2007 IEEE EMC Symposium opened on July 10. Technical papers covered a wider range of topics than ever before. The day started with the plenary session keynote speech by IEEE president Dr. Leah Jamieson of Purdue University.
In her address, Dr. Jamieson expressed concern about the future of the engineering profession. “There will be a disconnect if education doesn’t keep up,” she told the attendees. Jamieson was referring to the ever-changing demands on engineers and the fact that technology changes so quickly. “Technical knowledge doubles every five years,” she said. She noted that half of technology knowledge is gone in five years. Thus, by the time a freshman starts his or her career, most knowledge is obsolete. She also suggested that a bachelor’s degree is becoming a “pre-engineering degree” and that a master’s degree is almost a requirement now. (T&MW touched on these topics in “The future of engineering” in the September 2006 issue.) Dr. Jamieson concluded by saying “The biggest challenge for engineers today is managing complexity.”
| Read more about the EMC Symposium in: History abounds at EMC Symposium, EMC Symposium exits Hawaii, and Martin Rowe's blog. |
Dr. Tapan K. Sarkar, a professor at Syracuse University followed Jamieson with a lively discussion about James Clerk Maxwell, who created equations that describe electromagnetic fields. Because EMC engineers know Maxwell mostly for his equations, Sarkar highlighted Maxwell’s work in optics, colors, and gases. He then described Maxwell’s Equations and how Heinrich Hertz adapted the equations and reduced them from 20 to four.
Technical sessions
In “New Test Method for the Pulse Immunity of Microcontrollers,” Tao Su of Infineon Technologies told an audience that “in existing test methods, pulses are not well defined” and he showed experimental results that pulses can couple into power supplies and travel to microcontroller pins through voltage regulators. He proposed coupling and load circuits and a measurement method for recording pulses at IC pins. He then outlined a set of parameters that define a failure. He used a simulation to describe what happens to a pulse after it enters an IC package as part of the test method.
Dr. David Pommerenke of the University of Missouri-Rolla EMC Lab used ”Mode Suppressed TEM Cell Design For High Frequency IC Measurements” to describe a modification to a transverse electromagnetic (TEM) cell used to measure emissions from ICs that couple to PCB traces. The modification involved a set of parallel traces on the outside of the cell connected through resistors. The traces and resistors attenuate surface currents in the cell that don’t travel in a horizontal line between the cell’s input and output ports. This modification reduces resonances that degrade the cell’s performance.
You may not think that AM radio signals, with frequencies around 1 MHz, can cause EMC problems, but they do. Richard Weise of General Motors used “Modeling Coax Cable EMI Shielding Performance for Automotive AM Broadcast Band Applications” to show that holes in shielded cables let AM radio signals leak out and they can couple into other automotive systems. Weise described a method of modeling the cables, which lets you predict shielding effectiveness.
Dr. Marian Soinski of Czestochowa University of Technology in Poland described an EMC problem with household electric power meters in “Addressing an EMC weakness due to strong static magnetic fields.” The meters contain a brake transformer that slows the wheel. A magnet in the coil, when it comes within 8 mm of another magnet, can suffer permanent damage. The result: excessively high electric bills.
Dr. S.W. Siew of the University of Strathclyde ended the day by proposing a measurement system that measures EMC in electric-power substations that result from switching, coronas, and other events. Siew proposed fiber-optic and wireless systems.
The trade show
Given the location of this year’s symposium, it’s no surprise that the show floor looked different than in past years. Gone were many of the larger exhibits showing EMI antennas moving along masts and spinning on turntables. Booths were generally smaller and more subdued than at other locations. Nevertheless, there were several new product introductions.
Thermo Fisher Scientific introduced the ECAT Lightning Test System that tests aircraft for lightning to the DO-160 standard. This modular system tests using five pulsed and sinusoidal waveforms at up to 2000 A and 3 kV. “Many of the commercial aircraft lightning tests will be added to MIL-STD-461 by the end of 2008” said Thermo’s Mike Hopkins. The company also introduced its MZ-30 ESD simulator, which generates test voltages up to ±30 kV.
Three companies, AR Worldwide, Ophir RF, and Milmega, introduced RF amplifiers. AR Worldwide introduced the model 5S10G20 amplifier, which has a frequency range of 10 GHz to 20 GHz with 5 W minimum output power. Milmega’s RF350 produces 350 W at frequencies from 200 MHz to 1 GHz. Ophir RF introduced three high-power RF amplifiers. The model 5165 produces 250 W at frequencies from 800 MHz to 4.2 GHz. Model 5166 produces power levels to 500 W over the same frequency range. Model 7005 produces three channels (80 MHz to 1 GHz, 1 GHz to 2.5 GHz, and 2.5 GHz to 6 GHz) at power levels of 280 W, 80 W, and 50 W, respectively.
New and existing products for sale weren’t the only products on display this year. A 50th anniversary museum of EMC instrumentation filled the back of the exhibition hall. Instruments such as a Singer NF-105 noise and field intensity meter (see photo) reminded engineers of frequencies gone by.
