How should the grounding of the PAC shielded enclosure for intelligent controllers be handled?

The grounding treatment of the internal shielding compartment of the intelligent controller PAC (such as for wireless modules and high-speed processors) directly affects the shielding effectiveness. The shielding compartment should achieve a 360° low-impedance connection with the host housing, using conductive pads (such as beryllium copper springs) for continuous contact around the perimeter of the compartment, with an overlap interval of less than λ/20 (less than 15mm at 1GHz). The PCB ground plane inside the shielding compartment should be connected to the compartment via multiple screws or metal supports, with a connection point spacing of less than 50mm.

For cables passing through the shielding compartment, shielded connectors (such as D-Sub or RJ45 with metal shells) must be used, and the shielding layer should be terminated 360° to the connector shell, with the shell then overlapping with the shielding compartment. At the same time, waveguide ventilation plates should be installed at the compartment openings (such as ventilation holes). After grounding, the shielding effectiveness of the shielding compartment at 1GHz should be greater than 60dB, and the internal circuit radiated emissions should be reduced by more than 20dB, meeting the MIL-STD-285 or IEEE299 shielding effectiveness test standards.