Low frequency diffraction effects when shaping the offset gregorian reflector system of the SKA
Low frequency diffraction effects when shaping the offset gregorian reflector system of the SKA
复制标题
塑造 SKA 偏置公历反射镜系统时的低频衍射效应
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
M. Ivashina
中科院分区：
文献类型：
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作者：
D. D. De Villiers;R. Lehmensiek;M. Ivashina
平方公里阵列（SKA）射电望远镜的偏置格里高利反射器系统需要在非常低的频率下工作，在那里反射器变得（电）相对较小。通过对反射器进行整形来控制孔径分布可以提高系统的电气性能。由于该系统预计将在超过十年的带宽上运行，因此使用标准几何光学方法进行整形。本文系统地研究了衍射在低频下对各种形状几何形状的几个性能指标的性能的影响。结果表明，峰值位置的主要设计目标，接收灵敏度，是相对不敏感的衍射效应，使这种宽带形状的反射器的SKA的一个可行的选择。
The offset Gregorian reflector system of the Square Kilometer Array (SKA) radio telescope is required to operate down to very low frequencies, where reflectors become (electrically) relatively small. Shaping the reflectors to control the aperture distribution can improve the electrical performance of the system. Since the system is expected to operate over more than a decade of bandwidth, the shaping is performed using standard Geometric Optics methods. This paper systematically investigates the effects that diffraction will have at low frequencies on the performance of several performance metrics for a wide range of shaped geometries. It is shown that the peak position of the primary design objective, the receiving sensitivity, is relatively insensitive to diffraction effects, making such wide band shaped reflectors a viable option for the SKA.