摘要
A bidirectional deployable parabolic cylindrical reflector for an L-band synthetic aperture radar is presented in this study, in which a self-deployed antenna with low weight was designed. The antenna consists of four curved surfaces formed from thin sheets of composite materials connected by hinges along the edges, and the reflective surface is provided by the front surface. The edge profiles of connecting lines were obtained through geometric analysis. A scaled model, including design and manufac- ture, was demonstrated to validate the process from the folded state to the fully deployed state. The non-contact synchronous vision measuring method was used to test the basic frequency of the scaled model, and the test results gave the verification of the analyses. Compared with the existing unidirectional deployable antenna, this new type of bidirectional deployable antenna can be applied to larger-size antennas and has better performance because the glass-woven tape connections were substituted with more reliable hinges. Static, modal, harmonic response, and transient response analyses of the full-sized reflector structure were mod- eled with the commercial finite element （FE） package ABAQUS. The modeling techniques were developed to predict the struc- tural dynamic behavior of the reflector and the results showed that the first natural frequency was 0.865 Hz, and the reflector structure had good stiffness in three directions. This proposed structure has very high stiffness-to-mass ratio because of its hollow solid construction. A preliminary simulation of radiation properties of the parabolic cylindrical antenna, fed by an off-set linear feed horn array, was conducted to obtain the radiation pattern of the feed and the reflector.
研究目的:为了实现重量轻、驱动方式简单的可展天线,提出了基于复合材料的双向可展开、收拢的新型柱状抛物面天线。从几何分析、基频测试与理论计算等方面论证了该结构形式的可行性,为进一步的应用打下了基础。创新要点:基于剑桥大学提出的Deployable Support Structure,将反射面分成两块实现横向折叠,进一步减小收拢状态下的体积;采用非接触式方法进行了基频测试,提出了增加结构展开后刚度的几种方法,结果表明增加侧板和采用large curved tape springs作为边框的方式能够有效增加结构刚度。研究方法:制作了天线缩比模型,验证了收拢与展开过程;采用非接触式摄影测量法进行了基频测试;采用有限元方法进行了基频分析、动力响应分析和静力分析;同时初步分析了电性能。重要结论:本文实现了一种低重量、低成本的双向可展柱状抛物面天线结构形式,能够实现较小的收纳体积;文中提出的加固方案能够有效提高结构的基频。非接触式测量方法对于这类频率较低的柔性结构是可行的。
