Substrate for reducing electromagnetic interference and enclosure
US6191475A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 1997 |
| Grant date | Feb 20, 2001 |
| Priority date | — |
| Expiry date | Nov 26, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.