The Leading Source for EMI Shielding
Reliable Board, Enclosure and Cable Solutions
cable ferrites for interconnect cables, power
and telecom lines.
RFI-EMI architectural shielding
conductive metalized fabric wall coverings.
SENSITIVITY PROTECTION FROM OUTSIDE SOURCES OF RF INTERFERENCE
CONTAINMENT OF SENSITIVE, CONFIDENTIAL INFORMATION
• Medical facilities
• Business offices
• Mobile equipment, vehicles
• Test Labs
• Emergency call centers
• Sensitive electronic installations
• Computer, data processing
• Security centers
• Wireless LAN boundaries
• Military, secure facilities
• Financial centers
• RFID scanning areas
Clusters of electronic equipment with their necessary cables and interconnect devices of all types are generally
assembled collectively in equipment centers with central convenience in mind as one of the primary
considerations. However, once everything is in the same proximity, the cabling, power cords, and the equipment
being operated present a formidable RF consideration - either as an emitter of information or as a receiver of
unwanted interference signals. The assemblage of cables, in particular, is essentially an antenna farm facilitating
the transmission and/or receiving of RF signals. In many cases, further control of such signals is essential for
reasons of security, equipment operational integrity, confidentiality -- any, or all, of these reasons suggest
consideration of architectural shielding. Architectural shielding techniques allow an overall site correction in lieu of
having to address the conformance of each individual module or groups of equipment.
symptoms of the need
optical shielding for windows and similar
openings.
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Frequent computer crashes
Irregular operation of sensitive equipment
Suspect compromise of confidential information
Proximity of obvious local RF transmitters; i.e. radio, TV, production welders, MRI, airport radar
basic architectural shielding options
Industry consensus suggests that even a modest amount of precautions can provide at least 30dB of attenuation
without extravagant procedures such as line filtering, special doors, or metal walls. The logical approach,
especially for retrofits, is the addition of RFI-EMI suppression components one-by-one until the desired effect is
achieved. A suggested progressive approach follows:
conductive gaskets to bridge seams, door
openings, vents, bezels.
cable shielding overwraps for unshielded
cables.
1. Installation of cable ferrites where power and data lines enter the room, and where they enter the electronic
equipment. All cables and wiring need to be addressed -- just one cable or wire circuit without a suppression
device will compromise the integrity of the room. (See “Ferrites” section).
2. Conductive wall coverings at least on the walls and ceiling for retrofits; and preferably also on the floor under
floor tiles or carpeting. All six surfaces of a room are most desirable for the maximum effect. Seams must
overlap. (See “RFI-EMI Shielding Fabrics” section).
3. Grounding of mechanical penetrations into the room such as vents, pipes, metal door sashes, conduit.
These items can be connected to the wall covering shield. Common electrical grounding methods can be used.
4. Window shielding can be straightforwardly accomplished by adding a lamination of optically transparent filter
material. (See “RFI-EMI Optical Display Shielding” section).
5. Metal doors and sashes at entrance/exit points are needed to complete the effect of a shielded enclosure.
They can be very effective even without shielding gaskets.
6. Conductive shielding gaskets around door sashes, vents, windows and similar openings can increase
effectiveness. (See “RFI-EMI Shielding Gaskets section). If door closure pressures are a concern, many times
a compressive contact point every 6-8” is all that is needed by using short sections of gaskets or “shielding
contacts” (found in “Shielding Gasket” section).
7. Cable shielding along the length of the cable where it enters the equipment enclosure. Conformable
metalized fabric shields wrap around cables for wideband applications, and/or cable strap absorber shielding
can further increase the effect at discrete frequencies. (See “RFI-EMI Cable shielding section”).
8. Shielding tiles mounted at room corners (ceiling and/or floor level) dampen effects of reflections. Available
with pressure sensitive adhesive, or can be cemented in place. (See “Ferrites, Square Tiles” section).
installation and maintenance considerations
Construction contractors may not be familiar with the idiosyncrasies of RFI-EMI protection. So, emphasis on
proper installation, sealing and grounding is necessary. To sustain the room integrity, it must be realized that at
some point in the future the suppression protection level may degrade due to internal or external changes, or
wear and tear. Periodic audits can keep abreast of these developments.
shielding tile absorbers for upper and lower
room corners.
14100 McCormick Drive
Tampa, FL 33626
866.TECH.EMI (866.832.4364)
www.leadertechinc.com
T: 813.855.6921
F: 813.855.3291