It is very unfortunate to let you know, but we do not have any ADS nor AWR models available for these devices. They were effectively designed before ADS became popular.
The S parameters are given in the data sheets and one could use that information to create a model in spice that could satisfy your simulation requirements. Also, you can find large signal equivalent series source/load impedances measured at 3W output power.
The other choice would be to pick a device that does have a ADS model and go back and create a RF power amplifier around that new, alternative device. A MW6S004N would be my alternative recommended device to the MRF1513N. Similar in size and power but 28V rather than 12V and with an ADS model available.
The product summary page to the MW6S004N is:
https://www.nxp.com/products/rf/rf-power/rf-cellular-infrastructure/450-1000-mhz/1-2000-mhz-4-w-28-v...
I hope you will find these information useful.
Best Regards
Pavel
NXP TIC
