Shielded enclosure accuracy improvements for MIL-STD-461E radiated emissions measurements

Radiated emissions measurements performed in accordance with MIL-STD-461E require the use of a shielded enclosure to prevent measurement contamination by ambient environmental signals. Unfortunately, these metallic enclosures add errors due to resonant effects. A simple test procedure, validated by finite difference time domain modeling, has been developed to characterize the HF response of a shielded enclosure. This procedure was used to improve the accuracy of a typical shielded enclosure while remaining compliant to the requirements of MIL-STD-461E.