Study on longitudinal defocus performance of finite scan reflector antenna

With the development of phased array antennas, the finite scanning reflector antenna has become a hot research area. In order to meet the multi-function requirements of antennas in the new era, a longitudinal defocus characteristic based on parabolic deformation is proposed in this paper. A standard feed-forward reflector antenna is designed to make its feed fixed, and the defocus of the antenna is achieved by adjusting the focal length of the reflector, which is similar to the longitudinal defocus of parabolic antenna. A bifocal reflector is designed, and a bifocal reflector antenna is designed by the positive interaction of XOZ plane parabola and YOZ plane parabola, so that the focus of YOZ plane parabola is extrapolated and the focus of XOZ plane parabola remains unchanged to form a bifocal reflector. In this paper, the effectiveness of the proposed method is verified in one-dimensional arrays. The gain of the antenna increases by 1429dB in the EL direction compared with that of the standard parabola, and the beam width is basically unchanged. In addition, the proposed method can accommodate all feeders working simultaneously, and the power of a single feed horn is reduced and the gain is only 485dB lower than that of a spot-beam antenna. This method will provide theoretical support for the design of one-dimensional scan or two-dimensional unequal range scan of finite scanning reflector antenna.