一种小口径低副瓣卡塞格伦天线优化设计与仿真

Optimization Design and Simulation for a Small-Aperture, Low-Sidelobe Cassegrain Antenna

摘要: 针对小口径天线低副瓣的需求，提出了一种卡塞格伦天线的设计方案。天线主反射面0.8 m，为减少遮挡副反射面口径，取1/7主反射面口径为0.115 m；通过副反射面处增加扼流结构，改善初级反射场分布以及优化馈源支撑结构，馈源与副反射面采用PIM硬质泡沫支撑，给出了天线的设计思路。通过大量的电磁仿真计算，最终确定了天线的最优结构。仿真结果表明，在X波段工作频带内，天线增益高于34 dBi，第一副瓣低于−20 dB，波束宽度小于等于2.8˚。该天线具有口径小、结构紧凑简单、高效率、副瓣低等特点，为低副瓣天线提供了一种优化设计思路。

Abstract: To meet the low sidelobe requirement of small-aperture antennas, a design scheme for a Cassegrain antenna is proposed. The main reflector features a diameter of 0.8 m, while the sub-reflector diameter is reduced to 1/7 of the main reflector (0.115 m) to minimize blockage. The design approach includes implementing choke structures at the sub-reflector to optimize primary reflection field distribution, adopting PIM rigid foam supports for both the feed source and sub-reflector, and optimizing the feed support structure. Through extensive electromagnetic simulation calculations, the optimal antenna configuration was determined. Simulation results demonstrate that within the X-band operating frequency range, the antenna achieves a gain exceeding 34 dBi, first sidelobe levels below −20 dB, and a beamwidth narrower than or equal to 2.8˚. This antenna features a small aperture, compact and simple structure, high efficiency, and low sidelobes, providing an optimized design approach for low-sidelobe antennas.