Optimization design of multi-band ring-focus antenna with elliptical beam

A synthetical optimization design method of elliptical beam antenna with ring-focus structure based on the cutting shaped ring focus antenna and non-uniform rational B-spline surface (NURBS) is proposed for the requirements of multi-band, high efficiency, low side-lobe, and low-profile antennas with small-aperture. Firstly, the one-dimensional aperture distribution is parameterized by spline function and the electrical performance of the cutting shaped ring-focus antenna is quickly optimized. Secondly, the main- and sub-reflectors of the optimized antenna are parameterized by NURBS surface, and a multi-objective optimization differential evolution algorithm is introduced to optimize the efficiency and first sidelobe of the ring-focus elliptical beam antenna. A 410 mm×720 mm ring-focus elliptical beam antenna is designed and fabricated. The operating frequency covers Ku/K/Ka tri-band. The total efficiency of the antenna is greater than 49%, the first sidelobe levels are lower than –14 dB, and the voltage standing wave ratio is less than 1.44∶1. The measured results are in good agreement with the full-wave simulation results, which verifies the effectiveness of the proposed design method.