Absorbtion loss is given by A(dB) = 3.34 t (f(Mhz)Gu) where
t = thickness in mils (sorry, my book is not metric based) G = conductivity relative to copper (G = 1 for copper) u = relative permeability to vacuum Reflection loss is given by R(dB) 20 log [(K_1)^2/4K] which is approx 20 log [Z(w)/4Z(b)] for K>10 where Zw is the wave impedance and Zb is the surface impedance. For plane waves R(dB) = 108 + 10 log [G/uf(MHZ)] All this is from EMC Handbook, Vol 3, Don White Consultants, 1973. Richard Woods Sensormatic Electronics Tyco International -----Original Message----- From: Wani, Vijay (V) [mailto:vw...@dow.com] Sent: Friday, November 09, 2001 10:36 AM To: 'emc-p...@majordomo.ieee.org'; 'si-l...@freelists.org' Subject: emi shielding hello: as we know, threre are two main component of shielding effectiveness. (Absorbtion and Reflection). is there any way to find out.. what percentage of overall shielding is due to absorbtion / reflection for a given material? thank you in advance. Vijay Wani Dow Chemical ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
