Tungsten carbide/aluminum composite particles inhibit galvanic corrosion of aluminum. Harry Fuerhaupter, Potters Industries, Inc. ABSTRACT An ongoing issue in the design of reliable EMC shielding is galvanic corrosion of aluminum. How can an aluminum frame be protected from galvanic corrosion if it contacts an EMI gasket containing non-aluminum particles? Chromate conversion … [Read more...]
Crucial RF Shielding Selection Considerations
Gary Fenical Laird Technologies INTRODUCTION Designers must attenuate RF signals for various reasons. Since a product cannot be legally marketed unless it meets EMC requirements, designers must curtail RF signals above a certain limit. It is important to consider RF shielding materials at the beginning of a design project because choosing the correct kind of shielding upfront … [Read more...]
Understanding Shielding Effectiveness of Materials and Measurements in the Near-Field and Far-Field
When we treat the shielding effectiveness measurement with a uniform field, the results are similar for both near and far fields. Kermit O. Phipps and Philip F. Keebler EPRI EMC Laboratory, Knoxville, TN, USA INTRODUCTION Traditionally Schelkunoff’s shielding effectiveness equation is used universally in teaching and practice throughout the EMC community as a whole. In this … [Read more...]
Magnetic Shielding Design for Manufacturing
Sensitive electronic devices require protection from radiating magnetic fields. David Grilli Magnetic Shield Corporation, Bensenville, IL, USA Magnetic shielding for static and low frequency (<100 kHz), time-varying magnetic fields is accomplished by containing a specific device or item within a sheet metal enclosure of high permeability material. Typically, a sensitive … [Read more...]
Designing an RF Shielded Enclosure
Ron Brewer EMC/ESD Consultant Shielding has been with us a long long time. Early AM radios had shielded RF and IF transformers, shielded electron tubes, and compartmentalized shielded chassis. These shields were necessary to prevent RF pickup, feedback, and oscillation by the electron tubes, radiation from the local oscillator, RF contamination of the IF strip, and crosstalk … [Read more...]
Utilizing Overlooked Characteristics of Ferrites for Improved Printed Circuit Board EMI Suppression
ABSTRACT While nickel-zinc composition soft ferrites are routinely used for PCB EMI suppression, the consequences of DC and low frequency AC bias on a device's high frequency impedance has not been widely discussed in the EMC and magnetic component literature. Virtually all EMI suppression applications in DC and AC power filter circuits place two-terminal ferrites under … [Read more...]
Don’t Settle for Being Just an E3 Engineer—Become an E3 Advocate!
INTRODUCTION It is often the accepted practice for the E3 engineer on a program simply to provide his technical expertise on meeting EMI, EMC, EMP and other E3 requirements and to let others take the recommendations from there. Once the analysis and recommendations are complete, the decisions on how to implement the design are up to the platform design team. The truth be … [Read more...]
Towards an EMC Technology Roadmap
A technology roadmap is a tool for attaining the optimum development within a sector of technology. Marcel van Doorn Philips Electromagnetics & Cooling Competence Center, Eindhoven, the Netherlands INTRODUCTION This article expands earlier work on the concept of a technology roadmap for EMC technology.1 Just as a traditional terrestrial map helps insure that travelers … [Read more...]
An Emission Measurement System for the Twenty-First Century Based on Time-Domain Measuring Methods
More information and reduced measurement time can significantly improve the quality of emissions testing. Stephan Braun and Peter Russer Institute for High Frequency Engineering, Munich University of Technology, Munich, Germany For some time, measurements of electromagnetic interference have been carried out by super-heterodyne receivers operating in the frequency domain. … [Read more...]
Thermal and EMI Shielding Boost Design Reliability
Optimal shielding helps meet the challenges of cramming maximum functionality into minimal PCB space. Paul J. Stus Laird Technologies, St. Louis, MO, USA Advances in the miniaturization of electronic components has intensified the need for manufacturers to solve multiple problems simultaneously and earlier in the design process. Solving the issues quickly and early in … [Read more...]
