Experimental Spherical Near Field Antenna Test Facility, Phase 3. Volume 2: Study of an Offset Reflector Antenna with a Sagging Feed Support

摘要

A numerical model for satellite antenna simulations based on calculating the near field from the antenna by geometrical diffraction theory and then transforming to the far field was developed. For an offset reflector with a circular aperture and a nonrigid feed support, it is demonstrated that the impact of the sagging feed depends on antenna mount and orientation with respect to the measurement grid. Predicted far field pattern cuts show pattern degradations for different degrees of feed rigidity. The influence of reflector edge taper is also shown. Simulations for an idealized model antenna show that stiffening of the feed support considerably improves pattern prediction.