Brightness temperature emitted by radiometer calibration load at millimeter wave band

In this paper, the DVRT(vector radiative transfer theory of densely distrib uted random discrete scatters) model to calculate the brightness temperatur e emitted by radiometer calibration load is presented. It takes the multipl e scattering of isolation layer into account, which is neglected by the inc oherent homogeneous model often used in calibration. Hence, it works much b etter than incoherent homogeneous model at millimeter wave band. Furthermor e, the iteration of DVRT model is presented, and it proves that the incoher ent homogeneous model is just the zero-order solution of DVRT model. Some n umerical results are provided in the end.