[SI-LIST] Re: CPW r.o.t?

Brett,

Agilent AppCAD, which is a free download, has a CPW calculator.

We have used AppCAD to get close to the correct CPW structure
and then Ansoft 2D to converge on a more exact solution.

You can use HFSS to design them,  but getting a good co-planar
launch is a bit of a pain.  We ended up using HFSS to perform a final
verification of the design.

This process worked for a 10GHz package design.

regards,

scott


--
Scott McMorrow
Principal Engineer
SiQual, Signal Quality Engineering
18735 SW Boones Ferry Road
Tualatin, OR  97062-3090
(503) 885-1231
http://www.siqual.com


"Grossman, Brett" wrote:

> Anyone out there have a decent rule of thumb or closed form equation for
> approximating characteristic impedance of a CPW structure?
>
> Preferably something that doesn't involve me opening up my head and shaking
> my brain to try and remember what an elliptic integral of the first kind is
> (no Bessel or Henckel functions either please). I have found a few of these
> types in the literature but am really only looking for a sanity check at
> this point.
>
> My application is on silicon geometries. I designed some characterization
> structures that are off being fabbed and at the 11th hour threw on some
> additional coplanar structures. Now I did what I could to throw them into
> HFSS and optimize till I got a close match to a real 50 Ohm source, but I
> don't have infinite trust in my HFSS'ing with large aspect ratios nor
> infinite experience in designing CPW's.
>
> Any pointer would be appreciated.
>
> Best regards,
>
> -Brett
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
> List archives are viewable at:
>                 http://www.freelists.org/archives/si-list
> or at our remote archives:
>                 http://groups.yahoo.com/group/si-list/messages
> Old (prior to June 6, 2001) list archives are viewable at:
>                 http://www.qsl.net/wb6tpu
>





------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: