A Low Cost Screened Enclosure for Effective Control of Undesired Radio Frequency Emissions

This report describes a low cost, shielded enclosure that was developed to contain the electromagnetic radiation generated by electronic equipment in order to reduce the potential for radio frequency interference (RFI). The enclosure is made from thin wire mesh screening that is attached to a wooden framework for support. Allowances are made at both ends of the enclosure for large cable bulkheads. A special seam was developed to maintain a low resistive current path between adjacent sections of screening. Lossy dielectric material is used inside to greatly reduce leakage resulting from the cavity resonance effect. The physical behavior of the enclosure is modeled and compared with laboratory based measurements. A plot of shielding effectiveness versus frequency is presented.