The Study on the Adjustment Model of Sub-reflector and Engineering Realization Method
The gravity deformation of large reflector antenna causes the deterioration of antenna performance. In order to solve the problem, the method of real time adjustment of sub-reflector to reduce the influence of gravity deformation is proposed in the paper.
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The Study on the Adjustment Model of Sub-reflector and Engineering Realization Method Yuhu Duan
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Introduction
The surface accuracy of the antenna reflector is the main mechanical indicator of the antenna, which is closely related with the shortest operating wavelength. The real reflector is different with the theoretical reflector. The error includes the manufacturing error and the deformation caused by self-weight, wind load and temperature load and so on. Therefore, in the process of antenna design, not only the mechanical indicators and radio frequency indicator, but also the mecharonics should be considered [1]. With the increasing of antenna aperture and the operation frequency, the demand for the surface accuracy of the antenna reflector increases. The structural deformation of large reflector antenna is very large. And the gravity deformation is main reason for structural deformation. If the gravity deformation is reduced, the structural stiffness should be increased. So the antenna would become hulking. Especially for the millimeter wave antenna, greater demands are being placed on its surface accuracy. Therefore, many compensation methods for antenna deformation have been made. The method of using array feed to compensate the surface deformation of reflector is introduced in literature [2–8]. The phase of each unit in the feed array is changed and superimposed with the phase of the reflector to form the constant phase surface. However, due to the limit of weight, system complexity and requirements, the method of using feed array to compensate deformation cannot be used for some system. Yahya Rahmat-Samii and Robert A. Hoferer have made researches on the method of shaping the sub-reflector to compensate antenna deformation [9], and developed a fast and effective analysis method, which combines the Fourier Jacobi with physical optics and geometrical optics. The antenna efficiency of a 25 m antenna can be increased from 31 to 72% after the method is used to compensate the deformation in 43 GHz. According to Y. Duan (&) The 39th Institute of China Electronic Technology Group Corporation, Xi’an 710065, China e-mail: [email protected] © Tsinghua University Press, Beijing and Springer Nature Singapore Pte Ltd. 2018 R. Shen and G. Dong (eds.), Proceedings of the 28th Conference of Spacecraft TT&C Technology in China, Lecture Notes in Electrical Engineering 445, DOI 10.1007/978-981-10-4837-1_4
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the reaches of William A. Imbriale .et of JPC, The antenna deformation can be compensated through replacing sub-reflector by reflecting array, using a feed or feed array to excite low-profile reflecting array, and adjusting the exciting phase of each unit in array [10, 11]. The active reflector technology and the compensation method of jointly using array feed and transformable plate [12] are widely used in the deformation compensation of large reflector antenna. According to the analysis of the displacement of each node in the reflector, the translation includes two parts: one is the stiff movement o
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