hfss renormalization

Hello everyone,

Can someone explain what is the meaning of renormalization in ports definition? When do we have to choose it,what are the benefits and when are we sure that the s parameters that we get will be the same as if we measure the antenna? E.g If we have a microstrip-fed antenna and we choose the thickness of the strip to correspond to 50 Ohms at the desired resonant frequency are the s-parameters correct then?Do I have to choose renormalization or not?The same question applies to deembeding

Thanks