How do I design an RF enclosure to meet MIL-STD-461 radiated emissions limits?

Designing an RF enclosure to meet MIL-STD-461 radiated emissions (RE102) limits requires achieving 60-100 dB of shielding effectiveness across the frequency range of 10 kHz to 18 GHz. The enclosure design must address four coupling paths: direct radiation through enclosure walls (controlled by material conductivity and thickness), leakage through seams and joints (controlled by conductive gaskets and bonding), penetrations for cables and connectors (controlled by filtered connectors and bulkhead feedthroughs), and apertures for displays, ventilation, or access panels (controlled by mesh screens, waveguide-below-cutoff ventilation panels, and conductive window coatings). The enclosure material is typically aluminum alloy (6061-T6) with wall thickness of 2-5 mm, which provides more than 100 dB of shielding effectiveness at all frequencies through the solid material, but the practical shielding is limited by seam leakage and penetrations. EMI gaskets (conductive elastomer, beryllium copper fingerstock, or wire mesh) at all seams must maintain low-impedance contact across the joint. Every cable entering the enclosure should pass through a filtered connector (pi-filter or feedthrough capacitor) that attenuates conducted emissions before they can radiate from external cables acting as antennas.