How to create a FET model from datasheet in ADS?

[MajorEE]

I'd like to simulate the MRF1535N transistor for a VHF amateur radio amplifier in ADS, however, there is no model for this transistor. How would I go about creating a model from the specifications in the datasheet to simulate the system? I realize that without the actual die parameters it would not be perfect, but it should give me a little bit better confidence than simply throwing a matching network on both sides and saying "that should work", right?

I've searched through Keysight's videos as well as some of the literature and I have no idea where to begin. Any help would be appreciated!

[rfeecs]

What do you want to simulate?
The datasheet gives S-parameters and large signal matching parameters.
With that, you should be able to design with some confidence, much better than if you did a crude model:
http://www.nxp.com/assets/documents/data/en/data-sheets/MRF1535N.pdf

The datasheet doesn't give enough information to make an accurate model.  The typical way to make a model obviously is to fit the model parameters to measured data for the part.  Starting with DC parameters, measure IV curves.  For a power device, you may need to use pulsed IV curves to reduce thermal effects.  Then you adjust the model parameters so that simulating the IV curves matches up with the measurement.  Then go on to RF parameters, mainly capacitances, and package inductances.  Again, you simulate and match up measured S-parameters to simulated.  All this is a lot of work, so you have expensive programs like ICCAP to automate the process.  Or go to a company like Modelithics and pay them a lot of money to do it for you.

But obviously you are not going to do that.  The best you can do from the datasheet alone is simulate the model for the transistor only and try to fit parameters to the little data that the datasheet provides.  I would say this is not worth the effort, except for your own education on playing with the model parameters and learning what each one does.

As I said, the datasheet already gives you what you need to design a power amplifier.  Use the large signal output impedance provided, or calculate it from your load line and bias point.  Design the output match and bias network.  Then use the S-parameters to design the input match and bias network.  You can simulate gain using the S-parameters.  This should get you close enough.  The rest is tuning.

[rfeecs]

You probably saw this page:

http://www.nxp.com/products/rf/rf-high-power-models/models-for-ads-keysight-advanced-design-system:RF_HIGH_POWER_MODELS_KEYSIGHT

Unfortunately, no model for the MRF1535.  Maybe MRF1550 is closest, but it has about twice the capacitance of the MRF1535.