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