s parameters in microwave office

Hi!

I've a problem with S-parameter measurement in Microwave Office. I want to compare S-parameter from data sheet with a nonlinear transistor model (BFP450) but I don't know how to make a proper bias.

I've already downloaded data files from web:

http://www.infineon.com/cms/en/produ....html?q=BFP450

Thanks for help!

If you read the S-para file it will be indicated the trans part number and its bias condition.

OK, I know the bias conditions (Ic, Uce), but I don't know how to construct properly that DC bias in MWO. I just want to measure that S-parameters by myself using nonlinear model and compare it with S-parameters from data file for some Q points.

Please help guys, I don't know what to do. I have nonlinear transistor model and I just want to measure S parameters manualy. Could anyone show me a circuit scheme for MWO?

This topic was discussed many times on this forum.
S-parameters are only for low-signal (linear) evaluation, and they represent the measured data taken by the manufacturer at specific bias points.
Read this document from Agilent for more understanding of S-parameters and their test setup.
http://cp.literature.agilent.com/lit.../5952-1087.pdf

There is a new approach also from Agilent (X-parameters) which allows simulating S-parameters of non-linear devices.
http://www.agilent.com/about/newsroo...2009_bg.html#x

Jerdenk,

Since language is a tough one to learn to do it right, we say one thing but we mean another, then I don't know whether your question is a basic one of how to set up MWO simulation to compare S Para of a nonlinear model with the linear model data by the manufacturer or how to measure nonlinear model and compare to the linear model data.

I can help you a bit with the basic one because I did this thing a long time ago. Here is a picture of it below. If your nonlinear model result doesn't match the SPara, then you have to tweak your model. I haven't done this for decade so I don't remember how to setup MWO to tweak the spice model but I'm sure manju or some others can help you there. Or you have to google to find your answer.

The hard one then you just have read even more, as vfone mentioned above.

Thanks vfone and UKnowWhat, You helped me so much! It's working.

Hello jerdenk,

Yes what "UKnowWhat" mentioned is correct ...To get S-parameters from Spice model ...

You need to just create a schematic & import the spice model & add the ideal Bias Tees & finally spcify the Bias source & complete with ports & grounds...
Just sweep the project frequencies...& get the Output file as S-parameters...

If you want to tune Bias or Spice model to match the measured S-parameter its simple & just you need to set the optimization....