Space station Ku-band antenna performance degradation due to solar panel scattering interference

The space station Ku-band reflector antenna performance degradation due to solar panel scattering interference is analyzed. To characterize the scattering properties of the space station solar array panels, a series of radar cross section (RCS) scattering measurements were performed at Ku-band frequencies. The blockage effects of structures to a reflector antenna are traditionally modeled using "null-field hypothesis". The reflection and diffraction effects from the blocking structure are roughly approximated. The scattered fields from the blocking plate are accurately calculated using the geometrical theory of diffraction (GTD). The plate reflected fields, edge diffracted fields, and corner diffracted fields are all included. To verify the analytical model, measurements were performed. It was shown from computation and experiment that the solar panel scattering interference causes main lobe gain decrease and sidelobe gain increase on the sum mode patterns, as well as, null position shift and null depth decrease on the difference mode patterns.