whats the difference between the rEtotal and Gaintotal in HfSS?

hello,i have been confused about the rEtotal and Gaintotal in HfSS.i had seriously found it in the HfSS index,but it did not give me the pricise answer. thanks

rEtotal refers to the magnitude of the electric field vector (this will vary based on your input power, distance of farfield measurements and other similar parameters).

Gaintotal refers to the total gain (defined using normalized power over entire sphere and compared against an isotropic radiator, i.e., the standard IEEE definition)

thanks,got it!