In this paper we present a method for modeling the front door coupling between two nearby parabolic antennas as a function of some antennas' parameters: diameter, distance and rotation angle. First, a sensitivity analysis was carried out to choose the most relevant parameters. Second, we obtained a rational model for each configuration of parameters by applying four fitting methods and choosing the best fit. Third, we defined several mathematical functions to express the coefficients of the rational model as a function of the antenna parameters with their respective assumptions. Finally, a brief validation of the model is presented.