Absorptive electromagnetic shielding for high speed computer applications

An electromagnetic interference shield combined with a printed circuit board having components on one side and printed circuitry on the opposite side, comprising:

• (a) a first flexible mat of porous electrically lossy and magnetically permeable material,
• (b) a first sheet of conductive material bonded to one side of the first mat,
• (c) a sheet of insulating material bonded to the opposite side of the first mat, the insulated sheet being placed against the printed circuit side of the printed circuit board,
• (d) a second flexible mat of porous magnetically permeable material,
• (e) a second sheet of conductive material bonded to one side of the second mat, a third sheet of conductive material bonded to the opposite side of the conductive mat, the third sheet of conductive material having a plurality of openings passing through this sheet, said third conductive sheet being placed over the compoents on the printed circuit board, and
• (f) a conduit connected between the second and third conductive sheets to accept a fluid which may be passed through the conduit, the pores of the mat and the holes of the third conductive sheet to flow about the components on the printed circuit board to control their temperature.