[SI-LIST] Re: Traces don't cause EMI - really?

  • From: "Hassan O. Ali" <hassan@xxxxxxxx>
  • To: leeritchey@xxxxxxxxxxxxx
  • Date: Mon, 13 Oct 2003 12:18:54 -0400


I think you need to describe your measurement setup so that we clearly 
understand what you are talking about.

For example, you need to describe the following:

- transmission line type (microstrip, stripline, etc.)
- transmission line geometry (trace length, trace width, height above 
plane, trace/plane thickness, etc.)
- material parameters (substrate, conductors, etc)
- frequency range of measurement
- excitation source
- transmission line termination conditions (both ends)
- field probing technique  (near-field? far-field? how was that measured?)
- what you mean by "significant emissions"? - give a limit e.g. 20dB 
below FCC Class B)



Lee Ritchey wrote:

>I've tried several times to measure significant emissions from a single
>transmission line travelling over a plane at the distances above the plane
>one uses to create signal paths for logic circuits, the topic of concern in
>this thread, with no luck.
>I welcome measurements from others that supports the statement that traces
>over planes are significant sources of EMI.  So far, no one has presented
>such evidence.  Lacking such evidence, how can anyone make such claims?

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