How can I read Smith Chart in Virtuoso?

Hi Still Learning,
 
The paper based and Virtuoso Smith Charts should be the same (e.g. the center of the chart is in the same place,
the values on the chart should correspond with the paper chart).  Of course paper Smith Charts have much more detail!
What subversion of software are you using?  Is it possible to submit a Service Request so we can look at this more
closely...just in case you discovered a bug?   The Smith Chart readability was greatly improved in IC6.1.5 Virtuoso.
 
best regards,
Tawna

Hello Tawna,
Thank you for your attention to my issue. I am afraid I disagree with you, as there is no correspondence, whatsoever, between the paper-based and the Cadence-created Smith Charts.

For example, the Center of the Paper-based Smith Chart is always the number "1," and there is no "negative" number on the horizontal or vertical axes of the Paper-based Smith Chart; however, the Cadence-generated Smith Chart has variable numbers at its geometrical center as well as a mixture of positive and negative numbers on both axes. What does a negative number on the horizontal or vertical axes of the Smith Chart mean?

Furthermore, on page 519 of the document titled: "Virtuoso Spectre Circuit Simulator RF Analysis User Guide_7.2," there is a statement that reads as follows: "In the center of the Smith Chart, the values of S11 and S22 are greater than 1, so the center of the Smith chart is part of the unstable region." How does the author claim so? Where did he/she obtain the S11 or S22 magnitude from the Smith Chart? As you see, there is so much ambiguity in the documentation as well as the Software representation of the data.As a user, I am disappointed at how Cadence makes simple things complicated. As mentioned in my first message, I have used paper-based Smith Chart for 20 years, and am very familiar with its concept; however, Cadence makes me waste a lot of time to simply view some mundane information, which I can plot by hand on the paper. I hope an overhaul of the way Cadence develops its software happens so that we spend more time on innovation than dealing with software-related issues. I have been using Cadence for two (2) years, and, unfortunately, I do not see such a sign of improvement.Regarding your question, I am using IC 6.1.4 version of Virtuoso, and have no control over choosing the version, as my superior has that authority.

Thank you,

Still Learning

Hi Still Learning,
 
You may have run into a bug.  Please file a Service Request.
I am in a class right now, so I cannot dive deeply into this, unfortunately.
There is also a known bug with the Smith Chart that was just fixed in the
latest ISR of IC6.1.4 and also in IC 6.1.5.  The Smith Chart is
MUCH better in IC 6.1.5.
 
We are also improving the documentation - I completely agree that
it needs work.
 
I am very interested in hearing more about how you would like the Smith Chart
improved.  (I am sitting next to the Product Engineer for ViVA in this class.)
Please email me off-line and we can continue our discussion further.
 
 
Best regards,
 
Tawna Wilsey
tawna@cadence.com