HFSS - designing antennas for microwave ablation

Hello everyone
I hope everything is fine with you all.
I was wondering if any of you have designed a microwave antenna for Microwave ablation (treating tumours with heating)
I have a question about testing the antenna for reflection (S11) coefficient what boundries i have to use to get the correct results for radiation box ?

Just the radiation boundaries should be fine. Ensure they are roughly 1/4 wavelength away from the closest radiating surface.

Thank you so much for your help!
I have one more question about the steps i should take to generate a phantom to measure for example SAR and the estimated destructive volume within the phantom ?
what are the phantom used the most for such simulations and analysis

Thanks in advance!

Sorry, I couldn't tell you. I imagine there would be a fair bit of information in the literature, though.