From: George Tang (email@example.com)
Date: Tue Jun 05 2001 - 16:34:14 PDT
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 short waveguide. Calculate the attenuation of a waveguide operating
below cutoff. The radiated emission from one aperture may seem
insignificant, but when you have 100 apertures radiating in phase may cause
you to fail FCC A.
[mailto:firstname.lastname@example.org]On Behalf Of Neven Pischl
Sent: Tuesday, June 05, 2001 9:16 AM
To: email@example.com; firstname.lastname@example.org
Subject: Shielding Effectivness Question
I would appreciate if anyone could let me know if there are any references
(books, application notes, anythig ..) that deal with shielding efectivness
in cases when a source is close to an (electrically small) opening in a
shield (enclosure). In such a situation, the field will penetrate through
the hole and leak even if the size is much smaller than the wavelength. I am
particularly interested in situation when high-frequency source, such as a
PCB edge or a component operating at (say) 1 GHz and above is in proximity
of the venting holes, "small" gaps in the chassis etc.
All references that I have deal with uniform plane wave propagating
incident to a metal plane with a slot or hole, in which case it is enought o
have electrically small size of the opening (e.g. lambda/10) to efficiently
block any field propagation through the barrier. I can't find any useful
reference that deals in any analytical way with the situation I am intersted
I believe I might get some answers using some of the simulation programs,
but at the moment I am more intersted in the analysis of the problem than in
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