Reference · Secure facilities & shielding
Faraday cage
Faraday cage (RF shielded enclosure)
A Faraday cage is an enclosure of conductive material that blocks external static and non-static electric fields and attenuates radio-frequency energy. It is the physical principle behind RF-shielded rooms, TEMPEST enclosures, and the RF shielding required in SCIFs and MRI suites.
What it is
A continuous conductive boundary — mesh, foil, or sheet metal — that redistributes incident electromagnetic energy around its exterior, leaving the interior largely field-free. In practice it is built as a shielded room with treated penetrations for power, HVAC, and signals.
Why it exists
It is the fundamental way to keep electromagnetic energy from entering or leaving a space — whether to stop eavesdropping on compromising emanations (TEMPEST) or to keep outside RF from corrupting sensitive measurements.
Who it applies to
Secure-facility and shielding contractors: an RF-shielded SCIF, a TEMPEST enclosure, an anechoic chamber, and an MRI room are all engineered Faraday cages with different performance requirements.
Frequently asked
Is a SCIF a Faraday cage?
An RF-shielded SCIF is engineered as a Faraday cage — a continuous conductive enclosure that attenuates radio-frequency energy. Not every SCIF requires full RF shielding, but where TEMPEST protection is required, the Faraday-cage principle is how it is achieved.
Sources
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