IEEE 1302-1998 pdf download IEEE Guide for the Electromagnetic Characterization of Conductive Gaskets in the Frequency Range of DC to 18 GHz
1.2 Scope
This guide provides guidance on the selection of the best technique for measuring EMl gaskets for particularapplications, identifes limitaions and sources of errors of the commonly accepted techniques for measuringgaskets, and provides a basis for comparing the various accepted techniques. lt encompasses measurementsof the as-installed behavior of gaskets as well as manufacturing related, quality-control measurements.
1.3 Purpose
The purpose of this guide is to provide information that will allow the user of conductive gaskets to selectthe best measurement technique for a given application and to correctly interpret the data that is provided byeach technique.
2.References
This guide shall be used in conjunction with the following standards. A bibliography is included inClause 10 for further information.
ANSI/NCSL Z540-1-1994, Calibration-Calibration Laboratories and Measuring and Test Equipment-General Requirements.
3. Definitions, acronyms, and abbreviations
3.1 Definitions
All terms used in this document are in accordance with IEEE Std 100-1996.
3.2 Acronyms and abbreviations
ARP aerospace recommended practice
dB µ V/m decibels above a microvolt per meter
dB µ A/m decibels above a microampere per meter
EME electromagnetic environments
EMI electromagnetic interference
MSC mode-stirred chamber
SAE Society of Automotive Engineers
SE shielding effectiveness
TEM transverse electromagnetic
4. Factors affecting gasket performance Figure 1 illustrates a typical application in which the EMI gasket is placed underneath the lip of a cover in order to close the gap between it and the base enclosure. Other similar applications are under connector shells, waveguide flanges, filter cans and meter flanges, and in seams. The objective of the gasket is to pro- vide an electrical path across the gap in the shield, such that the impedance of the path through the gasket approaches that of a comparable span of the base shield. The impedance of the gasket is a function of its materials and construction, its geometry, and the interface between the gasket and the shield.
All gasket materials have resistive, inductive, and capacitive properties that may exhibit themselves over dif- ferent portions of the frequency band. Which property determines the gasket’s predominant characteristic depends upon the materials and construction of the gasket, as well as the geometry of the joint. Most gaskets can be considered resistive at low frequencies. Those gaskets that are constructed of metal filaments (ori- ented wires or wire meshes) and fingers or spirals typically appear as an inductance in series with a resis- tance. Gaskets that are formed from conductively loaded polymers typically appear as a shunt capacitance in parallel with a resistance. These complex impedances determine the effectiveness of the gaskets as fre- quency increases. Therefore, reliance on volume resistivity data taken at dc or at power frequencies can be very misleading.
IEEE 1302-1998 pdf download
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