Design of a 1 m dichroic subreflector for K/sub u//K/sub a/ frequency bands

The authors present the main results of a feasibility study of a 1 m dichroic subreflector having a separation between transmission and reflection bands on the order of 1:1.6 and qualified for satellite multifrequency antennas. The electrical design is discussed, and the expected subreflector electrical performance is reported. On the basis of the knowledge of measured dielectric constants, an accurate updating of the preliminary design and optimization of ring dimensions with respect to both resonant frequency and cross-polar requirements has been performed. A reliable characterization of the dielectric materials also allows an accurate numerical prediction of the radiation pattern of large dichroic structures.<>