Port power for comparing radiation pattern ADS and HFSS

Hello,

I have simulated an antenna using ADS and HFSS and I want to compare the radiation pattern computed by the two software but as you know the radiation pattern depends on the power of the feeding port. for ADS we can specify only the voltage in volts otherwise in hfss is the power in W that we can choose. Would you please tell it is possible to specify the power of the feeding port in ADS (or just the voltagei in HFSS)? How can I be sure that I have the same parameters for the feeding port ?

Thak you very much for your help

I think the solution is to plot a normalized fields, so the differents curves will be the same for the both softwares