Re: gEDA-user: trace calculation

[Gene Heskett <gene.heskett@xxxxxxxxxxx>]

On Thursday 05 January 2006 13:39, DJ Delorie wrote:
>> Why? Via doesn't have much more inductance than a piece of trace,
>> does it?
>
>At high enough frequencies, traces are waveguides, not just
>conductors.  Vias have nontrivial geometry relative to the signal.
>
>That reminds me of another optimization I'd like to implement in the
>future.  Instead of corners, treat all traces like elastic bands, so
>that they end up as sweeping curves (lines+arcs) with no corners at
>all (except for 3-trace nodes).  I want this myself just because it
>makes the board look pretty, but I wonder if gentle curves provide
>better waveguide performance than corners?

Probably not, unless they are above a good ground plane in the next 
layer down, and seperated from other traces far enough that they do 
not contribute any impedance anomolies.  Having closely spaced traces, 
all with the same separation spacing, and square corners, would 
probably be the choice to make on a crowded board.  Better yet would 
be rounded corners whose arcs all have a common radii origin point.

-- 
Cheers, Gene
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