Reduction of Forward Scattering from Blocking Struts in Reflector Antennas

A reduction of forward scattering from struts has been achieved by forming the strut cross section into a rhombic shape and making the surface approximately "hard". Both longitudinally corrugated and strip-coated surfaces are shown to give approximations to the desired boundary conditions. The basic properties of these surfaces have been studied numerically, and the induced field ratios of two struts have been measured. For the polarization with initially strong scattering, a significant reduction is demonstrated. For the orthogonal polarization with initially weak scattering, an increase is observed. This increase can be reduced by an optimized design of the surface geometry.