Re: microstrip impedance

[Kevin Thomas <kjt@cray.com>]

Evaluating equation 3, I get the same values (67 and 46 ohms).
I suspect that a calculation error was made in the original
document.  I did not hear about this discrepancy until now.

This error may be part of the cause of the 16% difference
between simulation and theory noted in the document.

-- 
Kevin Thomas    kjt@cray.com   tel 1-651-605-9072
http://lc.cray.com/~kjt/        or 1-800-284-2729 x6059072

jcschultz@mmm.com wrote:
> 
> I was looking at the S parameter examle documentation and cannot reproduce
> the impedance predicted in Eq 4  of the Sparameter.ps file.  Using the
> formula from Eq 1 of this document, I come up with 67 and 46 ohms
> respectively for the 2 and 4mm microstrip on a 2mm dielectric with k=5.
> 
> This agrees pretty well with other analytical approximations for
> microstrips but it does not agree with the sparam.ps documentation.
> 
> I was wondering if anyone has noticed a similar problem and if there is a
> solution.