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Time dependent S parameters

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Newbie level 5
Aug 1, 2012
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I have a set of S parameters corresponding to a dynamic simulation, eg 100 simulations of something moving past and antenna, time 0 to 1 ms (an s paramter result every 10us)

I'd like to use this set of S parameters in a downconversion simulation (whichever package that would suit, ADS, AWR, LTspice, or even matlab).

I'm wondering if anyone has any guidance on how to do this as my searching the web and inside help files isn't showing anything useful.

My current plan would be to make a component which would return an S parameter dependent on the time from simulation start and run a transient simulation, but I can't find a way to create the component I'd need.

I'm happy to interpolate between my measured s parameters if required, and I can limit this problem to a single frequency and maybe find a function to fit my data if that helped with the solution.

If anyone has any tips, I'd be very grateful,


I don't think this is possible. Your use of S-parameters is very unusual. There is no (meaningful) way to swap S-parameters during transient simulation, even if you custom-code your own component.

I think your only option is to create some behavioural model based on S-parameters.

BR, Volker (Keysight Certified Expert EDA)
--- Updated ---

Appendix: If we literally swap S-parameters, a simulation controlled switch bank would do the job, but that would be equivalent to the DUT "jumping" rather than a contiuous transition.
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Thanks for the reply, I was suspecting as much. Your switching idea is clever but I'd be worried about the jumps, I'm very interested in the phase of the S parameters for the downconversion so this does concern me a bit, but I might give this a try to see how it goes.

If not, I'm back with looking how to code this in matlab from scratch. Not ideal, but I'll learn something :)
My knowledge of time domain simulation is pretty minimal, I guess there is some integral method used rather than assessing each time step as it happens which is how I usually think about things like this.

best regards,

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