[SOLVED] Cadence AWR: How to use optimizer for model extraction?

[A_Coll49]

Hello,

I am trying to use AWR to extract an equivalent circuit model from S-parameter measurements I made on MIM capacitors. The method would be to build an equivalent circuit model of the MIM capacitor in the AWR schematic, designate component values as optimisation variables, and allow the optimiser to adjust these values until all 2-port S-parameters of the equivalent circuit model match the Touchstone .s2p file imported to the project. However, unlike ADS, it seems that you cannot compare two measurements in the optimiser, only compare a measurement with a fixed numerical variable. Is there another method I could use instead to get optimisation working? Any advice is greatly appreciated.

 

[BigBoss]

All Optimizers accept numeric values only. You can define a range which is appropriate for that.
You request "curve fitting" but no optimizer can do that..

 

[A_Coll49]

Thanks for the reply BigBoss. I've now found a way to perform what I wanted to do. In AWR, you can specify an optimisation goal with user-defined 'output equations'. An example of this would be Opt_S11 = ECM_S11 - Meas_S11. Then you can specify this equation as a measurement, thus it can be used as an argument for the optimiser. The goal can then be set to 'equal to' zero, so the Equivalent Circuit Model parameters are optimised such that the difference between ECM_S11 and Meas_S11 is as little as possible. As S-parameters are complex variables, separate goals are required for real and imaginary parts. Additional equations can be defined for the other 2-port S-parameters. I'll leave this here for anyone who needs to know, I couldn't find anything on this specific problem online.

See attached result of this method, with blue representing S11 of Equivalent Circuit Model and pink representing the measured device.