For all practical purposes the SE of commonly used metals is infinite except
at audio frequencies where skin depth becomes a problem. The intrinsic SE
of the material is always dominated by seams and apertures that are inherent
in any enclosure design. If you think that steel is less conductive
You can find it in Vol. 3 of The EMC Handbook published by Don White
Consultants, Germantown Maryland, (301) 948-0028 (verify that the area code
has not changed).
Richard Woods
-Original Message-
From: John Harrington [mailto:jharring...@ktlcanada.com]
Sent: Friday, September 28,
I thank all off you who answered my question.
Neven
-Original Message-
From: Neven Pischl [mailto:npis...@cisco.com]
Sent: Tuesday, June 05, 2001 12:16 PM
To: emc-p...@majordomo.ieee.org; si-l...@silab.eng.sun.com
Subject: Shielding Effectivness Question
I would appreciate if
Neven,
There are quite a number of books addressing the shielding effectiveness
analysis. Personally, I will recommend two of them:
1. White: EMC Handbook, Volume 3: Shielding
2. Ott: Noise Reduction Techniques in Electronic Systems, Chapter 6: Shielding
Hope this helps
Leslie
Neven Pischl
RE: Product Safety: A Matter of Law or Litigation?Look for a book on RF or
microwave. My favorite is Fields And Waves In Communication Electronics.
Look in the section on waveguides. Operate the waveguide below cutoff.
A small aperture in a sheet metal with finite thickness is essentially a
very
Neven;
In the near field one must know whether the offending emmiter is mostly
generated
from a magnetic loop or electric field antenna structure. Once that is known,
the
eventual transmitted portion can be computed. If your shielding is non Fe, Ni
or Co
and the source is of a magnetic loop
Here's an informal guideline that I use. If memory serves, I got it off the
Futurebus specification years ago. I imagine this guideline was based on
slower frequencies than we have nowdays.
1. Enclosure should have 20 dB of RFI attentuation at 5 Ghz.
2. Maximum gap shall be less than 3 mm in
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