EMC system engineers face trade-offs when selecting high power amplifiers for RF immunity testing. During testing, the amplifier must withstand high levels of reflected power. An appreciation of how reflected power affects an amplifier is important if well-informed decisions are to be made. This article uses a simple thought experiment to de-mystify this complex phenomenon and … [Read more...]
Integrated Inductive Component Reduces Radiated Emissions in Power Applications
The geometry of magnetic components can affect the incidence of unwanted low frequency radiation in the magnetic field.Gabriel Arianes, David Castillo, Raquel Garcia and Oscar Perez; Ferroxcube, Guadalajara, SpainINTRODUCTIONThe miniaturization trend has resulted in smaller components and greater board densities in electronic applications. This very density, which … [Read more...]
Design Considerations for Minimizing Large Aperture Effects in Shielding
Large aperture arrays can present special shielding challengesRon Brewer, Laird Technologies, Delaware Water Gap, PAShielding can be used at the systems or PC board level to protect sensitive equipment or circuits from both internal and external RF sources. Large systems can be placed in shielded rooms or even shielded buildings. However, regardless of the size of the … [Read more...]
Photonic Bandgap Structures and Their Application to EMC Antennas
PBG structures have been explored as a way of reducing harmonics.Vincente Rodríguez-Pereyra, Ph.D., ETS-LindgrenThe concept of photonic structures has recently been applied to the study of the microwave frequency (MW) range [1, 2]. Photonic bandgap (PBG) structures are analogous to a crystal lattice. It is known that in natural crystals there are certain non-occurring or … [Read more...]
Eliminating MYTHS about Printed Circuit Board Power/Ground Plane Decoupling
Bruce Archambeault, Ph. D. IBM Research Triangle Park, NC [email protected] Introduction The use of decoupling capacitors connected between the power and ground planes on a printed circuit board (PCB) is a common practice to help ensure proper functionality and to reduce EMI emissions from printed circuit boards. The proper number of decoupling capacitors, and … [Read more...]
Alternatives in EMI Connectors
There is no generic solution for all problems associated with I/O interfaces ORVILLE HAAS, WILLIAM E. KUNZSOURCES OF RF INTERFERENCE WITH CLOCK FREQUENCIES of a few gigahertz, today's electronic systems are using pulse edges in the subnanosecond range. Networking interfaces deliver data rates in excess of 100 Mbits/s (Fast Ethernet and FDDI—fiber distributed data interface) … [Read more...]
EMC Design Considerations for Medical Products
Collocation of sensitive medical electronic devices can result in equipment malfunction in medical settings ANTHONY A. DIBIASEINTERACTION BETWEEN MEDICAL products and their electromagnetic environment (EME) presents new challenges to medical device manufacturers, medical service providers, and the regulatory authorities who are responsible for insuring the health and safety … [Read more...]
Impedance Termination of Cable Shields to Reduce EMI Coupling
Surge damage as a result of long cables connected to low voltage data systems can be preventedRICHARD MEININGER & ROBERT BLOUCHThis article proposes a solution to the problems encountered when long cables are used to connect low voltage data systems, and either data interference or lightning surge damage is encountered. Three separate interference regimes are addressed: … [Read more...]
EMI Filters for Cardiac Pacemakers and Implantable Defibrillators
The use of ceramic feed-through capacitors, as well as specific filter designs and installation techniques, can make cardiac pacemakers immune to EMIROBERT A. STEVENSON, Maxwell Technologies Carson City, Nevada, USAUnder the coordination of Wireless Technology Research, L.L.C. (WTR), the interaction between cellular phones and cardiac pacemakers has been widely … [Read more...]
Introduction to Measurement Uncertainty for Antenna Calibration
Critical items need to be identified for a particular calibration method MIKE HOWARDThe purpose of this article is to introduce the reader to basic elements and concepts in the computation of measurement uncertainty for antenna calibration. Measurement uncertainty is a tool used to account for errors associated with a measurement system. Uncertainty can be used for … [Read more...]
