The Theoretical Analysis of Shaped Dual-Reflector Antenna with Ring Focus

Theoretical analysis of shaped dual reflector antenna with ring focus has been carried out. The reflectance caused by subreflector and antenna efficiency are computed by means of the field correlation method. We have found the optimum position of feed where subreflector VSWR is lower than 1.04. The antenna radiation patterns in the forward axial region and crosspolar radiation patterns are predicted by utilizing the classical method of physical optics. The comparison between theory and experiment results shows good agreement. These results indicate that this new type of antenna is characterized by its low sidelobe level, low cross polar level, high efficiency, and good match.