Feed adjustment method of reflector antenna based on far field

To improve the electrical properties of a reflector antenna, the reflector surface distortion is compensated to some extent and the feed installation error is reduced by adjusting the feed position based on far field. Considering the fact that the traditional method of best-fit paraboloid needs to obtain the accurate reflector deformation beforehand, a novel method to determine feed adjustment amounts based on far field is proposed, with no need to know the deformation. Based on aperture field method, explicit expressions of the sensitivity of far field to fitting parameters of the distorted reflector are established. Then fitting parameters and far field are linked with over-determined linear equations, and by measuring far field, the reflector deformation is approximately calculated based on least square method thereby providing guidance for the feed adjustment of the deformed reflector. In addition, the proposed method is also employed to determine the feed installation error, which is adopted instead of fitting parameters to describe the aperture phase error. Simulation cases show the correctness of the proposed method and the validity of the compensation of reflector distortion and the accurate installation of the feed.