From: sweir (firstname.lastname@example.org)
Date: Mon May 08 2000 - 11:53:29 PDT
Gross EMI is going to come from microstrips. However, striplines are a
concern as well. I think Michael has pointed out the common ways that
striplines can radiate, mostly due to the "impurities" of the real
world: vias, surface break-outs, proximity to the board edge, component
lead structures, etc.
Striplines have crosstalk considerations. There are various techniques for
making striplines more coax-like, including via fences that reduce some of
the problems due to the impurities Michael has described.
t 09:49 AM 5/8/00 -0500, you wrote:
>Thanks for responding. I appreciate your insight. My background
>is more theoretical and I wjould like to learn more about how SI
>engineers view things.
> >As much as I agree with that aspect, the notion I believe Vinu was
> >attempting to address, ( and I believe of practical value ) is that the
> >flux density surrounding T-line on a PWB as typically a microstrip or
> >stripline goes up as the impedance goes down and vice-versa.. For those
> >constructions a significant amount of the energy transmitted down the line
> >does so in the dielectric surrounding the signal and return etch. That
> >flux is free to intercept any antenna we place in the field, whether it is
> >a chassis slot, or a susceptor trace.
>I had not considered relating the characteristic impedance to a
>concentration of flux. This seems reasonable for microstrip geometries.
>I will give this some more thought.
>You also mentioned striplines. Are you suggesting that the radiation or
>coupling from a stripline is proportional to the characteristic impedance?
>This seems anti-intuitive to me.
>**** To unsubscribe from si-list or si-list-digest: send e-mail to
>email@example.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
**** To unsubscribe from si-list or si-list-digest: send e-mail to
firstname.lastname@example.org. 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
This archive was generated by hypermail 2b29 : Wed Nov 22 2000 - 10:50:13 PST