Shielding
This one-day seminar covers the proper design of shielded enclosures.
How shielding effectiveness varies with the choice of shield material,
whether metal or conductive coated plastics, is explained. The effects
of surface finish and corrosion are also discussed. Considerable
time is spent on the proper design of apertures in order to minimize the
leakage that they produce. Cooling holes, seams, and other apertures
are covered. Finally, the effect of shield penetrations, cable shielding,
and cable terminations on the overall shielding effectiveness is explained.
Although primarily intended for mechanical engineers;
electrical engineers, technical managers, and technicians who want a better
understanding of proper shielded enclosure design have also found the material
to be useful.
Outline
SOLID SHIELDS
Why Do We Shield?
Shielding Basics
Beware of the Shielding Effectiveness Killers
Required Levels of Shielding
Shielding Mechanisms
Shielding Effectiveness
-Absorption Loss
-Reflection Loss
Dependence on Shield Properties
Universal Absorption Loss Curve
Magnetic Materials
Total Shielding Effectiveness
Conductive Coatings on Plastic
Selective Shielding
APERTURES
Types of Apertures
Slot Antennas
Maximum Linear Dimension vs Frequency
Multiple Apertures
Wire Mesh Screens
The Number One Rule of Shielding
Joint Impedance
Conductive Finishes
Contact Impedance Requirements
Transfer Impedance
Corrosion Control
EMC Gaskets
Waveguides Below Cutoff
Viewing Apertures
Component Holes
Shielded Enclosure Design Options
Grounding & Bonding of Shields
Avoiding Floating Metal
Measuring Shielding Effectiveness
PENETRATIONS
Unintential Radiators
Cable Penetrations
Enclosure Voltages
Common-Mode Currents on Cables
Shielded Cables
Shield Termination Methods
The Effect of Pigtail Terminations
Connector Backshell Grounding
Diagnostic Techniques
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Henry Ott Consultants
48 Baker Road Livingston, NJ 07039
Phone: 973-992-1793, FAX: 973-533-1442
e-mail: h.ott@att.net
March 7, 2002