Substrate for reducing electromagnetic interference and enclosure

Abstract

A substrate for reducing electromagnetic emissions is provided. The substrate may include a plurality of ground layers, signal layers and power layers. All of the layers other than the ground layer are provided with a ground ring that may extend around the perimeter of the layer. The ground rings are electrically coupled together by ground stitching or vias that are randomly spaced. The random spacing of the ground stitching is based on the operating frequencies of the integrated circuit devices mounted on the substrate. Additional shielding may be provided by providing a cover assembly made of any conductive material that is coupled to the exposed ground rings on the uppermost and lowermost surfaces of the substrate. The cover assembly is coupled to the exposed ground rings in a randomized pattern. The device provides a virtual electrical ground cage in which the internal signal layers are totally enclosed, thereby reducing electromagnetic emissions.

Dependencies are inferred from the claim text.