Technical specifications:

The feed design has been optimized for high cross-polar isolation and the illumination of the reflector in order to achieve high isolation between the antennas to help compensate for the reduction in shroud length.

A monotonic main beam shape has been achieved with this illumination. The low edge illumination of the reflector as well as providing high inter antenna isolation also results in very low sidelobes as demonstrated by computation and measurement.

Accurate beam alignment is achieved by high construction accuracy and symmetry of the antenna structure as demonstrated by physical measurement of the mechanical components. Alignment is within 0.1 degrees.

Figure 1. Polarimetric feeder design.

Figure 2. Plots of the co- and cross-polarized antenna gains.