I have been using plane shielded loops for over 15 years. Small magnetic loops allow localizing defects to small areas and use of small samples. I don't claim objective figures, but by comparing the material under test to a known good shield (i.e.: galvanized iron sheet) and to air, one gets a good feel for the merit of the material in hand.
Cortland ====================== Original Message Follows ==================== >> Date: 31-Jul-00 20:53:05 MsgID: 1072-33864 ToID: 72146,373 From: "Douglas C. Smith" >INTERNET:[email protected] Subj: Shielding Effectiveness - or when a dB is not a dB Chrg: $0.00 Imp: Norm Sens: Std Receipt: No Parts: 1 List-Post: [email protected] Date: Mon, 31 Jul 2000 20:53:52 -0700 From: "Douglas C. Smith" <[email protected]> Subject: Shielding Effectiveness - or when a dB is not a dB Reply-To: "Douglas C. Smith" <[email protected]> Hi All, Shielding effectiveness is normally measured using plane waves (relatively far from the source). This method of measurement for shielding effectivenes does not always correspond to the way a shielding material is used. It is especially true when shielding material is incorporated into small products, such as the new wave of wireless devices on the market. If you rely on shielding to keep different parts of a product from interfering with each other, correlation of specification to use is especially important. The August 2000 Technical Tidbit on http://www.dsmith.org (or http://emcesd.com) describes a simple method of shielding effectiveness measurement that can be easily done in the development laboratory. This measurement method can give a better measure of shielding effectiveness that industry standard measurement techniques when the shield is close to the source being shielded. Has anyone here who is into shielding used something like this method which uses magnetic field loops? Doug -- ----------------------------------------------------------- ___ _ Doug Smith \ / ) P.O. Box 1457 ========= Los Gatos, CA 95031-1457 _ / \ / \ _ TEL/FAX: 408-356-4186/358-3799 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-----( ) | o | Email: [email protected] \ _ / ] \ _ / Website: http://www.dsmith.org ----------------------------------------------------------- ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected] ====================== End of Original Message ===================== ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
