多频段环焦型椭圆波束天线优化设计

针对小口径低剖面天线的多频段、低旁瓣和高效率的需求，提出一种基于切割赋形环焦天线和非均匀有理B样条（non-uniform rational B-spline，NURBS）曲面的环焦型椭圆波束天线的综合优化设计方法. 该方法首先采用样条函数将一维口面场参数化，针对赋形切割环焦天线进行第一次快速优化设计；然后，用NURBS曲面将优化后的天线主副反射面再次参数化，引入多目标优化差分进化算法，以天线效率和第一旁瓣为优化目标，对该环焦型椭圆波束天线进行第二次优化设计. 应用该方法设计并加工了一个410 mm×720 mm的环焦椭圆波束天线，工作频率覆盖了Ku/K/Ka三个频段，天线总效率达到49%以上，第一旁瓣低于–14 dB，电压驻波比小于1.44∶1. 实测结果和全波仿真结果吻合良好，验证了本文设计方法的有效性.

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.