1997 Meetings

The linked titles of some meetings are the presentations speakers provided.

December 9, 1997: "EMC Research Projects - Radiated Field Coupling to Signal Cables, Power Circuit Cross Coupling" by Mary Wilson, SFSU/Bay Networks, Michael Mack SFSU, Edwin Salgado, SFSU/Silicon Graphics Inc. - Intro Dr. Pantic-Tanner, Director, SFSU School of Engineering

Abstract: On December 9, the Santa Clara Valley Chapter of the IEEE EMC Society will hear presentations on two EMC research projects being carried out by the San Francisco State University (SFSU) Electromagnetics Group.

In the first presentation, the effects of radiated fields inducing unwanted common mode and differential mode currents onto signal cables are evaluated. Digital and analog control systems are exposed to the external electromagnetic noise produced by electrostatic discharge, EM fields from transmitters, and other sources. As a result the systems can start malfunctioning and the susceptibility problems arise. One of the main mechanisms of coupling of these external fields to the control systems is through the cables and wiring that act as receiving antennas. In this presentation the modeling results of two-wire lines excited by a uniform plane EM wave are analyzed using three different models. A lumped parameter model which is valid for lower frequencies and yields a simple analytical solution that is suitable for estimation purposes. For higher frequencies a transmission line model and an antenna model are used to accurately represent resonant behavior. This topic is being presented by Mary Wilson and Michael Mack.

In the second presentation, the effects of power supply switching noise on power distribution traces coupling onto adjacent signal lines are evaluated. Many state of the art microprocessors and ASIC integrated circuits are now powered by voltages that are less than the standard 5 VDC. With this reduced operating voltage, the susceptibility of the signal lines to noise increases. At the same time, these new operating voltages require on-board DC to DC converters that generate a substantial amount of switching noise. This switching noise can couple onto the signal lines, causing the system to malfunction. The noise generated can also have substantial harmonic content that can excite resonant structures within a system, causing it to exceed EMC conducted and radiated emission limits. Normally, power is distributed via power and ground planes in printed circuit boards. But because many of the circuits connected to these low voltage microprocessors and ASCII still operate at a nominal 5 volts, adding an extra low voltage plane adds cost, so this is not always a viable solution. The lowest cost solution is to route the low voltage power for the micro-processors and ASICs through wide traces on the same layers that contain signals. This increases the coupling efficiency between the power traces and adjacent signal traces. In such cases, one can use traditional trace to trace crosstalk coupling models to analyze the problem. This presentation discusses several rules for circuit board design that minimizes this interference. This topic is being presented by Edwin Salgado.

Bio: Michael Mack is a senior student majoring in Electrical Engineering at San Francisco State University. Michael has worked for several years in the communication and professional audio field as an technician and sales engineer. He has also worked as an intern with an acoustical engineering firm to develop software programs used to calculate noise criteria curves for HVAC systems.

Mary Wilson is an SFSU senior student majoring in Electrical Engineering with special emphasis on communications. She is also a full time EMC engineer at Bay Networks, where her emphasis is MOM and SPICE modelling of radiated emissions from cable arrays and microstrip geometries. She has also been an Electronic Technician for 8-years including 4-years in the United States Coast Guard working with RADAR systems.

Edwin Salgado is an SFSU senior student majoring in Electrical Engineering and Computer Science with a minor in Mathematics. Edwin has worked as an intern in the AT&T Communications group writing code to simulate two antennas for wireless communication systems, and as an intern in the VSG EMC group at Silicon Graphics using HP VEE, NEC/INCASES Method of Moments, and Cray Research LC Finite Difference Time Domain modeling tools to do EMC computations as well as assist EMC engineers with performing EMC measurements. Edwin is currently working as an intern at Silicon Graphics in the Graphics Software Group as an Operating System Software Debugger.

November 11, 1997: "Understanding Intrinsic Printed Circuit Board Capacitance & Decoupling Methodology" by Neilus O'Sullivan, Sun Microsystems, Menlo Park, CA

Abstract: Much investigation has been carried out into the area of intrinsic board capacitance of power distribution systems on multi-layer printed circuit boards (PCBs). While its benefits are broadly understood, very little tangible evidence exists as to whether or not it provides an effective solution for combating radiated EMI in complex state of the art computer systems.

In this presentation, the EMI characteristics of a densely packed high speed computer motherboard involving clock and bus speeds up to 200MHz with signal rise times in the order of 400 pico-seconds is analyzed extensively. Actual measured comparisons of radiated emissions and power bus transfer impedance are presented for the original motherboard and for the case of the motherboard with additional power and ground planes included. A discussion of general decoupling methodology for multi-layer boards will also be presented.

Bio: Neilus O'Sullivan received his B.Eng. degree from the University of Limerick in Ireland in 1989 and his Ph.D degree in electromagnetics from the same university in 1995. He has worked for Analog Devices B.V. as Test Characterisation Engineer and in 1989 joined automotive electronics manufacturer, Kostal Ireland as Research and Design engineer. From 1991 to 1995 he worked as consultant engineer to the broadcast industry in Ireland. At present he is employed by Sun Microsystems as EMC engineer at their Menlo Park facility. He has published a number of papers and presentations on various aspects of EMI, but his main area of interest is that of EMI control at printed circuit board level.

October 14, 1997: "The Resurrection of an Absorber Lined Chamber" by Ronald Pratt, NCE, Hewlett Packard Co., Santa Clara, CA

Abstract: The quality of a test site is based on demonstrating conformance of measured Normalized Site Attenuation (NSA) to ideal values published in ANSI C63.4. Celebration is appropriate if the data falls within the +/- 4 dB limits but more work will be required if the site fails to meet these limits. This paper describes an extension of the existing test process that may prove useful for evaluating the performance of a site. Further analysis of the data can help identify the root cause of the problem.

The method was successfully applied to develop a strategy for improving the performance of the ten meter absorber lines chamber at the Hewlett Packard Hardware Test Center in Cupertino. An overview of the analysis of the site and a discussion of the retrofit will be presented.

Bio: Ron Pratt joined the Hewlett Packard Company in 1967 and spent most of his career developing microwave instruments for signal generation, network analysis as well as power and noise figure measurements. EMC was always an important part of that work and for the last several years he has focused on those problems. Ron received his BSEE from New Jersey Institute of Technology in 1967. For almost 20 years Ron taught a very successful microwave measurements course at Foothill College. He is a contributing author to the Reference Data Engineers: Radio, Electronics, Computer, and Communications and the Electronic Instrument Handbook. Ron is a member of IEEE EMC Society and is a NARTE certified EMC Engineer.

September 9, 1997: "Annual Social and Business Planning Session"

May 13, 1997: "Lessons Learned in Designing PCBs for EMC" by John B. Howard, EMC Consultant for ElectroMagnetic Compatibility by Design

Abstract: The EMC Problems associated with hardware/PCB design often result from outdated or misapplied practices. This presentation will highlight a few of these practices and offer some alternatives and solutions. The perspective will generally be from experiences gained in improving the EMC engineering on a variety of new high performance products. Discussion will focus on the impact of vias, power/ground plane noise, bypass capacitance, transmission line structures, and the application of ferrites. Some thoughts will be offered on emerging chip/package EMC issues.

Bio: John Howard is currently working as an independent EMC consultant with over eighteen years of EMC engineering experience. John has been an EMC consultant for the past four years. He earned BSEE and MSEE degrees prior to working for several bay area companies as a hardware design engineer, engineering manager, scientific researcher, and EMC design engineer. He has authored or co-authored several technical papers on the subject of design for EMC compliance. John is also the lecturer for EMC courses offered worldwide by the University of Wisconsin. He is a NARTE registered professional EMC Engineer, a Senior Member of the IEEE, and Chairman of the University Grant Subcommittee of the IEEE EMC Society Education Committee.

April 8, 1997: "Numerical Methods in EMC" by Prof. Jose Perini, Syracuse University

Abstract: Since it is much more important for the user of these techniques to understand their physical principles rather than their mathematical foundations, the presentation will be mostly on the physical principles. From this it will be easier to understand the limitations of each technique. There are a very large number of Numerical Techniques that can be used in EMC. Due to the short time available I will only talk about three of the most popular ones. They are the Method of Moments, The Finite Element, and the Finite Difference Time Domain Techniques. If time permits, I will touch a little on the Geometrical Theory of Diffraction.

Bio: Professor Perini was born in Sao Paulo, Brazil. He graduated from Escola Politecnica de Sao Paulo, as an Electrical and Mechanical Engineer in 1952. He worked as the Manager of Radio Maintenance for one of the largest Airlines in Brazil and then returned, in 1956, to Escola Politecnica as an Assistant Professor of Electrical Engineering. In 1958 he came to Syracuse University where he obtained his PhD in EE in 1991. During this time he also consulted for General Electric Company in the design of Television Transmitting Antennas. He then returned to Brazil to his teaching position in Escola Politecnica. In 1962 he returned to Syracuse University to teach Electrical Engineering where he retired in 1991. During his stay at Syracuse he had many research contracts with the Air Force, Navy, and Army. He was also a consultant for many industries. Professor Perini has published and presented many papers and has also given many invited tutorials. He is a Fellow of the IEEE, a Life Member of the EMC Society, and a NARTE Certified Engineer. He is also reviewer for the IEEE Transactions on EMC, AP, MTT, and Education.

March 11, 1997: "Joining of Two Conductors for EMI/ESD Protection" by Richard Haynes, Richard Haynes Consultants

Abstract: One of the most common trouble spots is the electrical discontinuity at the interface between two conductors. Also, secondary ESD events can be caused by electrical discontinuities at interfaces between two conductors. Material choices of such joints are usually compromises between the minimum impedance and the maximum corrosion resistances of the interface. It is possible to calculate the time to failure for a given set of conditions. This talk reviews: (1) conductive materials and surface finishes commonly used in the proper choice of materials. Also discussed are design guidelines for joints that should be used in electronic products.

Bio: Dr. Richard Haynes graduated with a Ph.D. in electrochemistry from the University of Pennsylvania and completed a Post-Doctoral in the areas of Li, N, H Magnetic and Electron Spin Resonance in Metal Solutions. After a distinguished 26 year career he recently retired from AT&T Bell Laboratories. During this period, Dr. Haynes developed expertise in: metal finishing, industrial ecology, reliability, corrosion and film growth, battery technology for portable products, EMI shielding technologies and design, and applications of magnetic probes to EMC. His work has resulted in 7 patents (2 more pending) and over 35 technical papers with 53 technical presentations to professional societies. Dr. Haynes is a member of The Electrochemical Society, American Electroplaters and Surface Finishers Society and ASTM serving on several committees such as Metal Finishing and EMI Materials. He worked on a team that was awarded the IR100 Award given for the Best Industrial Development during 1983 and more recently earned the AT&T Global Manufacturing and Engineering 1995 Technical Excellence Award. Dr. Haynes started a consulting business and serves as consultant for several large companies.

February 11, 1997: "Taking the Black Magic Out of Grounding" by Hugh W. Denny, IEEE EMC Society Distinguished Lecturer

Abstract: Grounding has long been considered a nemesis of the electronics and communications world. EMC practitioners have often referred to grounding as "black magic." The reasons for the mystery surrounding grounding are that (1) it is often left to chance or is ignored until the design is hardening, (2) low frequency grounding techniques are presumed to work at radio frequencies, and (3) fundamentals of electromagnetics are ignored. This presentation reviews the basics of grounding networks and sets forth design principles for all frequencies. The needs of all "users" are considered in the development of an integrated approach to grounding.

Bio: Mr. Denny, for 35 years, lead research teams on the development of grounding, bonding, shielding and lightning protection guidelines for the United States air traffic control system, the Department of Defense long-haul communications network, the Metropolitan Atlanta Rapid Transit system traffic control facilities, and communications and information processing complexes. For 20 years, he directed research faculty conducting sponsored programs in electromagnetic interference control including lightning protection, electromagnetic pulse and high power microwave hardening, and program management guidelines. Mr. Denny has developed electromagnetic interference (EMI) test procedures and instrumentation, and electromagnetic compatibility (EMC) specifications and limits for equipment and systems, both domestic and international. For 15 years, he provide designs and guide specifications for the grounding, shielding and lightning protection of military and civilian facilities.

January 14, 1997: "High Intensity Radiated Fields (HIRF) Testing" by Roger A. McConnell, CKC Laboratories, Inc.

Abstract: When solid state communications equipment started being installed in aircraft, more than 30 years ago, it was discovered that this equipment was very susceptible to failure from electrical sources both within and outside the aircraft. It was slowly learned that modern equipment required more protection than had been required with vaccum tube equipment. With the advent of digital avionics and fly-by-wire electronic control of flight critical functions, it became imperative to closely examine the possibilities of harmful interference from both on board equipment and from external sources of radio frequency fields.

HIRF deals with the susceptibility of aircraft to interference from external sources, such as short wave broadcast, military IFF equipment, and radar systems, both ground based and airborne. In this talk, some actual HIRF incidents will be described, and the history of HIRF concerns from the early 1980 s to the present will be reviewed.

Bio: Roger McConnell has been with CKC Laboratories, Inc. in Mariposa, California since 1986. He retired at the end of September 1996 and is now working as a part time consultant to CKC. His primary EMC activities have been in open field range calibration, anechoic room performance, and energy transfer in EMP. He has been a member of the Society of Automotive Engineers AE4R Subcommittee which has been advising the Federal Aviation Administration in connection with the threat to aircraft from high energy RF fields. Prior to his employment at CKC, Mr. McConnell was employed for 24 years at the Stanford Linear Accelerator Center in technical support of high energy physics research. He specialized in the design of very high power CW RF systems, accelerator cavities and phase stable transmission lines. He has co-authored a number of papers relating to particle accelerator radio frequency systems which have appeared in the IEEE Symposiums on Nuclear Science, and has authored six papers on open field range calibration and EMP which have appeared in the IEEE Symposium on EMC. He is a graduate in Electrical Engineering from the University of California at Berkeley.