Accurate Modeling of the Interaction between Feeds and Dichroic Mirrors

This paper presents an accurate method to analyze the interaction between feeds and dichroic mirrors. The methodology is based on the plane wave expansion of the field impinging on the dichroic surface and employs the MoM/BI-RME approach to calculate the transmission/reflection coefficients of the dichroic mirror. This method allows for taking into account the real physics of the problem, thus identifying the actual behavior of the dichroic/feed system. The importance of such method is particularly evident in case of dichroics that present performances strongly varying moving away from the nominal incidence angle. Two examples are reported to validate the proposed method and to show its performance