Patent ID: 6538903
Filing Date: 2003-03-25
Classification: G06F,H05K

Abstract:
A method for reducing electromagnetic radiation emanating from a computer enclosure, wherein the computer enclosure encloses at least one source of electromagnetic radiation within the computer enclosure and includes at least one unshielded opening in the computer enclosure through which an undesirable amount of electromagnetic radiation from the at least one source is capable of passing to an exterior of the computer enclosure, the method comprising:connecting a riser card to a system board within the computer enclosure, the riser card being a PCB having at least one ground layer and at least one signal layer, the at least one ground layer being grounded and providing a substantially continuous conductive layer within the riser card, whereby the riser card extends transversely from the system board and divides an interior space of the computer enclosure into two compartments, a source compartment containing the at least one source of electromagnetic radiation, and an unshielded compartment having the at least one unshielded opening in an exterior wall thereof, and wherein the at least one ground layer is positioned towards a side of the riser card facing the unshielded compartment relative to the at least one signal layer; and positioning the riser card in the computer enclosure so that an outer perimeter of the ground layer of the riser card is surrounded by a sheet metal barrier, with at least a substantial portion of the riser card inside of its outer perimeter not covered by the sheet metal barrier, whereby the riser card and the sheet metal barrier together form an EMI shield between the source compartment and the unshielded compartment, whereby the undesirable amount of electromagnetic radiation from the at least one source is prevented from passing to an exterior of the computer enclosure.