Re: [SI-LIST] : Shielding Effectivness Question

About this list Date view Thread view Subject view Author view

From: Doug McKean (dmckean@corp.auspex.com)
Date: Tue Jun 05 2001 - 12:26:20 PDT


RE: Product Safety: A Matter of Law or Litigation?Neven,

I did some rather intensive analysis of shielding effectiveness
over the course of several weeks a while back. Results were
extremely informative.

I've read a couple of fields and waves books for slot analysis.
Rau is the one I prefer. I'm at work, but I'll get the name of
it and the ISBN as well.

I've done some experiments with "small" stubs and loops with
reference to wavelength. And I was surprised to find a rather
predictable approx -10dB rolloff per several decades from lo
to high frequencies. Results were debatable.

Converting the wire stubs over to slots by way of Babinet
makes me think that the roll-off for slots is similar. And with
this information, I started my little analysis in the chamber
on products.

I haven't seen nor am I really worried about problems with
holes. Unless of course they're big. Slots are your worst
violator. This is because of the mechanism by which apertures
work. It's, in my opinion, more difficult to impose a voltage
differential across a round hole than it is across a slot.

Slots are more directional than wires by a factor of roughly 10.
That makes your product particularly susceptible during emissions.

Anywho, I'll get you the name of the book and specifics for ya.
And if you want, maybe you can pop over here to do some testing.

- Doug McKean

**** To unsubscribe from si-list or si-list-digest: send e-mail to
majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP.
si-list archives are accessible at http://www.qsl.net/wb6tpu
****


About this list Date view Thread view Subject view Author view

This archive was generated by hypermail 2b29 : Thu Jun 21 2001 - 10:12:15 PDT