Omar M Ramahi

US Patent:

20050104678, May 19, 2005

Filed:

Sep 10, 2004

Appl. No.:

10/937251

Inventors:

Shahrooz Shahparnia - Hyattsville MD, US
Omar Ramahi - Bethesda MD, US

International Classification:

H04B003/28

US Classification:

333012000

Abstract:

Electromagnetic Bandgap (EBG) structures are embedded between adjacent power planes in a multi-layer PCB to decrease the emanation of Electromagnetic radiation induced by power buses, signal layers, as well as to suppress the switching noise. EBG stages with different stop bands are cascaded to create rejection over a wider frequency region. The cascading can be performed in series, or may be formed in a variety of arrangements such as a checkerboard design or concentric ribbons positioned along the perimeter of the PCB. Each EBG stage is composed of conductive patches and via posts extending from each patch, which are positioned at a predetermined distance from each other. By surrounding the source of the noise with EBG stages, a sufficient suppression of electromagnetic noise over specific frequency bands of interest is achieved.

Author:

Omar M. Ramahi

ISBN #:

0792374622