A scalable model for nonlinear systems operating in feedback

The state-of-the-art in nonlinear models is that many approaches exist if the system is operated under open loop conditions. However, in a microwave context, open loop systems do not really exist as any parasitic coupling will inevitably introduce a feedback path. Microwave systems operating in modern transceivers are always pushed to their limits, resulting in a nonlinear behavior of the device.

You will start from a Bond graph or a flow graph formalism to describe the behavior of the system, using the structure of the model to try to identify the linear dynamics and the nonlinear response of the device.

The idea is to use more than one model to gradually increase the modeling power, hence the complexity, of the model. To start with, you will use the best linear approximation of the system in a single operating point. Next, you will combine these linear models over a range of operation conditions using a local modeling/interpolation method. If time permits, you will identify a full nonlinear model for the device under test.

Theory: 30%, Simulation and identification: 50% Experimental verification: 20%



Yves Rolain
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