A novel approach for the design of dichroic mirrors for deep space antennas

This paper presents a novel approach for the design of inductive dichroic mirrors used in the beam-waveguide feed system of deep-space antennas. The traditional design approach is based on the optimization of the performance of the mirror under single plane-wave illumination at the nominal incidence angle. This methodology does not allow for controlling the radiation pattern transmitted by the feed/dichroic system. A novel design strategy, consisting in optimizing the dichroic mirror also considering the overall feed/dichroic system, permits to overcome the limitation of the traditional approach. A dichroic mirror operating in S/X/Ka band has been designed with the two methodologies and its performance is discussed in the two cases.