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Panel Adjustment and Error Analysis for a Large Active Main Reflector Antenna by Using the Panel Adjustment Matrix | IEEE Journals & Magazine | IEEE Xplore

Panel Adjustment and Error Analysis for a Large Active Main Reflector Antenna by Using the Panel Adjustment Matrix


Abstract:

Active panels are generally applied in large aperture and high-frequency reflector antennas, and the precise calculation of the actuator adjustment value is of great impo...Show More

Abstract:

Active panels are generally applied in large aperture and high-frequency reflector antennas, and the precise calculation of the actuator adjustment value is of great importance. First, the approximation relationship between the adjustment value and panel elastic deformation is established. Subsequently, a panel adjustment matrix for the whole reflector is derived to calculate the reflector deformation caused by the actuator adjustment. Next, the root mean square (rms) error of the deformed reflector is expressed as a quadratic form in the matrix form, and the adjustment value can be derived easily and promptly from the corresponding extreme value. The solution is expected to be unique and optimal since the aforementioned quadratic form is a convex function. Finally, a 35 m reflector antenna is adopted to perform the panel adjustments, and the effect of the adjustment errors is discussed. The results show that compared with the traditional model, where the panel elastic deformation is not considered, the proposed method exhibits a higher accuracy and is more suitable for use in large reflectors with a high operation frequency. The adjustment errors in different rings exert different influences on the gain and sidelobe level, which can help determine the actuator distribution with different precisions.
Published in: IEEE Transactions on Antennas and Propagation ( Volume: 69, Issue: 10, October 2021)
Page(s): 6351 - 6363
Date of Publication: 05 April 2021

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I. Introduction

Large reflector antennas have been widely used in deep space exploration, radio astronomy, communications, and other applications, owing to their simple structure, high gain, and narrow beam [1], [2]. With the development of reflector antennas to have large apertures and high frequencies, such antennas must operate in the open air due to their large apertures and are thus inevitably affected by external loads such as gravity, temperature, and wind. In such cases, the reflector may be deformed, leading to a considerable deterioration in its electromagnetic (EM) performance [3]–[6]. Moreover, owing to the high frequency, a high surface precision must be ensured, which notably increases the difficulty in the structure design [7], [8]. To ensure high surface precision, active main reflectors with adjustable panels have been widely applied to large reflector antennas operating in the millimeter or submillimeter waveband [9], [10], such as the 110 m Green Bank telescope with 2004 panels supported by 2209 actuators, and the 65 m Tianma telescope with 1008 panels and 1104 actuators. As shown in Fig. 1, each panel of the active main reflector is supported by four actuators and can be adjusted to the locations of the ideal reflector or best fitting reflector. Thus, the deformation measurement and panel adjustment calculation of the deformed reflector are two particularly important research areas [11]–[13]. However, in this article, we focus on the panel adjustment calculation and the effect analysis of the panel adjustment error on the EM performance of the reflector.

Active main reflector of the 65 m Tianma telescope in China.

References

References is not available for this document.